Because much to the contrary of what farmers claimed, it does affect the game outside of just what they're doing.
Arguably the most pronounced affect was on the market. Things that were deemed "desirable" cost billions of influence, more than a non-farmer could ever hope to earn unless they were extraordinarily lucky and happened to get a desirable drop that they could sell. Unfortunately, that was extremely rare. I would sometimes go weeks without getting a single purple drop, for example, and then when I did, I'd get something that was generally considered junk, worthless on the market. There were a few IOs that eventually I just resigned myself to never possessing because I didn't farm.
This is especially brutal to new players, which the game desperately needed to survive. When you come into the game and a bunch of people are all purpled-out to the point where it seems hopeless that you'll ever meaningfully contribute to a team, it doesn't take long before you leave the game.
Related to that affect is the affect on the tone of the player base. One anecdote in particular sticks with me. My roommate Belle used to play for hours at a time helping people out, and she detested farming. Once, she joined a team advertising for a task force, but before she did, she specifically asked if it were a "speed run" team, and the leader told her no, it was just a normal run. So she joined, and the team proceeded to speed run the task force. I was sitting there watching her as they blew through mission after mission, taking every shortcut they could, even doing things like deliberately failing missions just to get to the next mission faster. They would finish some missions before she could even get inside the instance. Finally, she nicely told them that she didn't know this was going to be a speed run, apologized, and left the team.
I was already annoyed that this is what had become the de facto standard of what was considered a "normal" run. But what came next utterly disgusted me. Some of the people on the team started sending her private /tells cursing her out for leaving the team before they fought whatever big baddie was at the end of the task force. Being a kinetics defender, they were expecting her to be around at the end so that she could use Fulcrum Shift and whatnot to buff the team and debuff the enemies. When she left the team, that meant that they were going to have to fight in the final battle for five minutes instead of the two or three they were expecting. Thus, for the next 15 minutes or so, she received a slew of insults and accusations of griefing the team by leaving.
I tried my best to get her to petition the people cursing at her, but being Belle, she wouldn't do it, and I knew that the GMs didn't respond to petitions sent on behalf of someone else, so they basically got away with it scot free. But it really pissed me off because again, that was the kind of thing that probably would have caused a relatively new player to abandon the game and move on to something else.
Then, of course, there's AE. At the time, no mainstream games that I knew of had such a feature that allowed user-generated content in the game. Being a roleplayer, and being someone who had all sorts of cool ideas for missions and storylines, I was super stoked about the thing. But after creating a few stories and getting one-starred because it wasn't farmable enough or because someone objected to a mission because it didn't give enough experience, and after looking at the arc list and pretty consistently seeing stupid farming arcs ranked at the top of the list, I was done with it. A feature that I thought had the real potential to be revolutionary and really set CoH apart from every other grindfest became THE grindfest that I abhorred.
Look, I know that some amount of farming will always happen. Players will always want to reach that next level, get that next new shiny, and knock out a mission or two specifically to get there. That's not what I'm complaining about. I don't even mind if every once in a while I see someone broadcast that they're looking for a team to just do a quick ITF or whatever. But when speed runs and farming become the norm and people start getting upset at people who aren't playing the "right" way, when I see one of the nicest people I know on the verge of tears because she left a team and had the audacity to negatively affect their precious XP/sec stat, when I basically give up on the market because it's just a cesspool of junk and items that are hopelessly expensive, yeah, I take a dim view of farming.
Of course, part of this is partly because I come from a background of pencil-and-paper roleplaying. Yeah, it was cool to find a +3 Sword of Whatever, but you rarely had such blatant min-maxing going on, and when it was encountered, it was strongly frowned upon; many a DM I knew would take great pain to specifically pick on your character if you were what we referred to as a "roll player"--that is, a player who cared more about the dice than the story and characters.
The thing about an MMORPG, the thing that is supposed to separate the genre from others such as RTSes, FPSes, etc., is that it's supposed to bring that sort of philosophy to the gaming world, that it's not so much about "winning" as it is to put yourself into the role of the sorcerer, or the steampunk pirate, or the spandex-clad invulnerable behemoth. At its best, City of Heroes was very good at that, and AE had the potential to really push that idea to a new extreme. At its worst, though, it was just another grindfest, and to me, the farmers, power-levelers, and min-maxers were directly responsible.
I have to respectfully disagree. I think farming, in general in games, especially MMOs that start to get heavy on the micro-transactions, is a symptom of how the game's economy (both in game currency and out of game currency wise) and what kind of player base they want to court, is set up, not a cause.
The price of super rare purples was so high
because they were so rare and good, not because farmers gathered up the money to buy them. If they were junk or common, then there wouldn't need to be farmers and they would stay inexpensive to the game. They were so rare to encourage the players to do a small amount of content numerous times, especially older content that was frankly less interesting. This is precisely why so much stuff started to become character 'bound' when they started to roll out the Incarnate stuff.
You might get mad at people wanting to speed run say, an ITF in 15 seconds, but realistically that's what people are going to do (if they can) when you expect them to run through it 29 thousand times to get some fate threads or what not.
The wider the gap between SO/IO got, the more 'bad behavior' you were going to find. Because people don't have infinite time (or patience) to play a game so you have to ration their time in your design.
Honestly, I loved CoH and I felt like out of all MMOs I've played it did this best. But it wasn't perfect, by any stretch of the imagination, and the worse it got with things, and the bigger divide between the 'haves' and 'have nots' and the more power divide between the 'hard core' and the 'casual' the worse behavior you'll find in any game. (And I find this is multiplied exponentially if the game favors PvP over Co-Op or PvE as well).
Frankly, AE as anything but a grind wheel to power level folks was doomed from the start. AE really as a roleplaying engine was more for you and your friends to experience, rather than random people. There was just too many players involved. Even if all of them worked in good faith to make nothing but RP content, there would be a giant sea of missions to get lost in.
Honestly, I didn't mind AE as a power leveling tool. To me it greatly enhanced the game and allowed me the leisure to pursue arcs at a slower pace. I didn't feel, for instance, that I had to grind arcs at lightning pace to get anywhere. I didn't feel like if I wasn't min-maxing my time to XP ratio that I was wasting both.
And it was great for ALTs that had builds that didn't bloom until level 20-22, especially pre-Fitness being universal.
Nothing kills my enthusiasm for playing a character, no matter how much I love the concept or story, of having to slowly hobble myself along for literally
months until the character 'worked' right.
I felt like every second I wasn't basically farming purples bosses side kicked to a character that didn't suck was a waste. I'd get this sort of taste of dread in my mouth every time I'd open up the character select screen and see the character that I wanted to play at level 22 but they're sitting there at 10 or 12 or something, taunting me. Especially way early on, in CoH's history, when just getting to a mission could be a nightmare.
Heck, then I wouldn't even want to play the character even
when they got good because I always had that sort of reflexive dread like "Oh, here comes the lame guy that I made that can't accomplish squat". I'd pass them to select the same guy that I had forever that I knew I could get into the game and
do something with.
Then it became a sort of self fulfilling spiral, when I would have limited time to play, so I figured I could either further the guy that was already making the big bucks, or try to carry weak mcsucksguy along being miserable, making the latter feel even weaker or slower, making me no want to play them, etc.
When AE came out, it helped alleviate that a lot.