Insofar as no game can please everybody all the time, you're right. But I find it difficult to understand how someone who loved the L1-50 game could love something so incongruent as the iTrials.
Speaking for myself, mostly because I didn't find it incongruent. To me, there's a very straight line you can draw from the L1-50 game which is about power progression, through the invention system which is about enhancement progression, to the incarnate system that is about a higher level hybrid of that.
Now, in terms of the incarnate *content*, it did start off as a large scale raid system, but they were adding other content to it, and if anything it was a far superior experience in my opinion to the original raid system - Hamidon. It wasn't too dissimilar from, and could be seen as an extension of, zone events, mothership raids, and other larger scale content.
Its also fair to say that the incarnate raid content added something for players who wanted something larger scale than the 4-8 task force system, so in a sense it was also an extension of the task force/strike force system.
I felt a unique kinship with the kind of players who formed the Taxicab service, or who would see a newbie struggling a bit and dump some Inf on them just because they could. I felt very little kinship with most of the iTrial lovers.
You say that like those were two different exclusive groups of players.
From what I gather, the datamining seemed to indicate that only a tiny % of the game's population experienced the Incarnate system, and honestly I'm not that surprised.
That was not my understanding. In terms of overall percentages, it was probably not high, but that's because most players did not have level 50 players: it took a lot more investment in time than most players appreciated to get a character to 50, and all the end game systems were targeted at them. In terms of players who had at least one level 50, I think the percentage was probably reasonable. Particularly if you include all players that at least possessed a slotted Alpha power, which was usable outside of iTrials.
Even from a design perspective, the Incarnate system felt like a massive compromise, as if the devs were stuck between a rock (l33t players seeking end-game progression) and a hard place (a codebase completely hostile to raising of the level cap and the expansion of the power set system that was already straining from the existance of primary, secondary, pool, and epic/patron sets). On the one hand, it could be argued that the Incarnate system was better than no system of advanced powers at all. But the take-away for me is that any "spiritual successor" to CoH under development today ought to seriously re-think its approach to the "end game" and not make it feel like all the other MMOs out there because, frankly, most of us loved CoH precisely because it didn't try to feel like all the others (which mostly just wanted to feel like WoW).
So here's the thing. There was nothing preventing the devs from raising the level cap. I'm not sure why you think the gamecode was "hostile" to that, except that I think you think that would have been a good idea.
It would have been a terrible idea. There's no specific reason to raise the level cap of a game unless your intent is to *stratify* the players at the cap. A level 50 has content available to her that a level 40 doesn't (barring sidekicking into it). Levels are *gates* in game design, and you add more when you want to add more gates. City of Heroes didn't need more content gates, because it didn't have enough players to justify more stratification at the top. Moreover, the players that did reach the cap had spent a long time there and had built up their characters to exist at the cap through builds and inventions: raising the cap would simply force them to restart those builds from scratch.
The incarnate system was not in my opinion a "compromise" in this sense. It was actually the correct target to aim for. Rather than adding more "levels" to the game the Incarnate system created a way to advance through gaining powers and abilities without having to invalidate level 50 builds. Furthermore, much of that heightened ability was *only* usable in the end game content. That made it a completely optional enhancement to the game. Had the devs created (all) incarnate abilities that could be used everywhere, they would have started a chain reaction of power creep where they would have to rebalance PvE content for stronger players - but that would leave non-incarnates behind.
The fact that some players said they didn't like it and thus did not participate is part of the strength of the system: even moreso than the invention system it could be safely ignored for those that did not want to participate. If you didn't participate in the invention system, you'd quickly notice the massive strength difference between you and your fellow players in teamed content. But except for the benefits of Alpha which were not as noticeable, you wouldn't notice a strong difference between you and your incarnate brethren in teamed content outside of the iTrials.
When the invention system was introduced in I9, there was a deliberate intent for it to affect the entire game. It was technically optional, but the design intent was to essentially replace the standard enhancement system with something better. It was designed to change the entire game, and it did for those that paid even a small amount of attention to it. The incarnate system was designed with the opposite intent: to disrupt the conventional game as little as possible, and in that it mostly succeeded. Changes like restructuring power sets or adding powers and slots or raising the level cap all disrupt the convention game in many ways subtle and not so subtle. The devs didn't avoid doing those things because they couldn't, they avoided them because they were all bad ideas if you wanted to preserve the L1-50 environment while simultaneously introducing very powerful character progression content.
I should also express my opinion that "most of us" is a phrase to be used sparingly, and only with unimpeachable justification. I'm generally not comfortable doing it, and I don't think anyone else should either.