I pre-ordered ESO, and was in a couple of the later closed betas. I played it for a couple of months, took a six month break, played for another month, took another, longer break. That's not because I think the game is mediocre; far from it. I enjoy the hell out of it, and love the gameplay. I prefer playing a classical mage type, because of the lightning theme I have going with my sorcerer, but I've also had some fun with a lifesteal-based nightblade. I see great potential in the game, but I also have some concerns.
First and foremost is the teaming mechanics, or rather, the lack thereof. They've taken some steps in the right direction with dungeon scaling, and I understand that the way zones are set-up preclude any means of scaling the world with the player, and that's fine. What they ought to add, however, is something like CoX's sidekick and mentoring systems, because as it is, teaming with friends, assuming you can get any to play in light of the missteps already made (i can't), is a nightmare of people having fun and outleveling their friends. Something like the XP->Inf toggle would be nice, as well.
My next concern is additional skill lines. Legerdemain is nice enough, I suppose, though I personally have no real use for any of the skills therein. I am aware that the Thieves Guild and Dark Brotherhood will be making their way into the game, probably early next year. I really hope they don't screw up the lore here, because according to the history, the time period ESO takes place in is around the years when the Dark Brotherhood was just being formed, so they don't exactly have a lot of history to draw on for fluff at this time period. However, skill lines that even a brief glimpse through the forums will show you that tons of people are clamoring for, such as unarmed, are apparently nowhere near a concern for the devs. I personally know of one person for whom the lack of fisticuffs is an absolute deal breaker. Not sure why some people are lobbying so hard for a spear skill line, as well, but the Dark Souls games have given me a better appreciation of the benefits of polearms. Some of these posts have rough ideas for skill line abilities already, just waiting for ZOS to pick them up and refine and balance into something amazing. Jewelcrafting is another thing that plenty of people have requested, without response from devs.
Spellcrafting and player housing. These things have barely been touched on, although I know there's a few threads where data mining brought to light a rough, early, framework for spellcrafting that looks fairly sound. Housing might make woodworking actually useful beyond one or two pieces of gear, heh. Or a masonry skill line.
And my final complaint, is in regards to the priority between making the game an Elder Scrolls game, and making an MMO. We could have had something like what Ark: Survival Evolved does, individually hosted worlds, for those who wish to play alone or in a local/private session. I imagine that character transfers/duplication could occur between private servers and something like an official server, so long as the client's game data was not out of sync with the main server. If it is out of sync, perhaps they could give you the option to run a cache verification like steam does, to match your data with theirs as a means to reduce hacking. The always only online aspect of the game seems to indicate that ZOS developed ESO first as an MMO, and an Elder Scrolls game second, which is the incorrect priority for those. Some might say that that decision proved ZOS' unworthiness of the IP.
As it stands, I play alone, except when dungeons require me to group up. Haven't even touched the late game stuff, and I've been in Cyrodiil a couple of times, simply to gather lorebooks and skyshards. Did have a funny moment when I stumbled across two players from another alliance doing the same thing, and we silently cleared a delve together. Just needed to get all of this out there and off my chest. And there's no way I'd be posting it on the official forums; have you seen the vitriol that follows reasonable suggestions in nearly every post? No, thank you.
