No, the current approach is fine and comes with a fair amount of merit in it's intent to promote a healthy community dynamic through reputation and meaningful character choice. Personally I'm happy with this decision and in my book it's pros outweigh the cons.
The only inflexibility right now is your bloodline choice plus that of your personal time. Everything else about your character is and or will be changeable, including age and height with potions etc.
Commitment is important for this kind of game where reputation is key and your role in the world is more defined by your ability to perform certain tasks. If you're an indecisive person or have issues committing to one role in particular, then of course this is going to be a hard pill to swallow.
I have to agree with this and I am, what is often referred to as, an alt-oholic. I am the indecisive player who likes to experience games from different character builds. On top of that, I am a thematic player, meaning everything from my name to my race to the build I play lines up in a way that might be considered hardcore RP, though I don't espouse "thees" and "thous". This is my burden, and it has been the same for me since I first starting playing D&D in the mid 80s. With all of this, I am still on board for one character per account. Why?
Well, precisely for the reasons Woody posted, and to add support to it, I site SWG. Outside of UO, the original SWG has to be the most widely beloved sandbox-ish MMORPG ever created. Sure, it had the golden IP which drew people in, but they stayed because of its features, and is fondly remembered for the same. In SWG, what you chose to be mattered, and influenced your game experience in such a way that a multi-character account could not. For example, I had an entertainer character who gained in fame, and was hired by a guild to "perform" at their guild house. My brother also played at the time, and he was well known as a crafter. On another one of us was a well known duelist, and could stand apparently afk, and Empire characters (the duelist was a rebel) would never attack him. This could happen, in large part, because of the one character per account restriction.
Some may argue that you could achieve the same with multiple characters per account. However, I think that it is obvious that notoriety and reputation is built upon time spent in the game as that character, filling that niche. Had I not played my performer in the local cantinas frequently, having my time split between different characters, I would have not been known as a top entertainer. Anyone could have done what I did, if they would have had many characters to play with, and we would all just be yet another nameless, generic example of X. Most games are filled with interchangeable clones. But, because of the single character restriction, I will always remember Reejo, Lynch, and Blind Lou Sugar (and others might too).
EDIT: Let me add that you could change your character "class" in SWG as well. But, it was a big process to level it up, such a big one in fact that to unlock Jedi you had to take your character to max level in all classes. Of course, once you did that, you sort of lost what you were known for. It was basically starting again, and I think that is good because it did provide a "way out" for the bored player, looking for something new. We should not forget that MO2 allows for this too.
EDIT II: In addition, the call for for multiple characters per account can come from multiple places, like my alt-oholism. However, there are a few player types that I know desire multiple characters per account, and these play types are usually not great for the game overall. Yeah, this is a bit of a hot take, and some are probably going to be offended. I am not trying to offend here, only point out. Here are a few:
1. Mechanics-Meta-Man: This player often wants to be able to follow the meta uninhibited, play the "most powerful" character, and nothing else is as important. They tend to reduce the game to button pushing and a mode of mechanical gameplay that could exist as easily in a MOBA, FPS or fighting game. This guy or gal wants to have multiple characters to make that pursuit easier. When archery is OP, they switch to their archer, when it changes to magic, they have a wizard waiting. If not mitigated somewhat, It often leads to cookie cutter builds, bandwagoning, and a real lack of diversity.
2. The One Man Economy: This player dislikes the fact that certain clades get boosts to different types of crafting and gathering, and thinks that they should be able to cut out player interaction for the sake of their independent success and enjoyment. They want a stable of crafter/gatherer types, so they can harvest trees with this guy, refine ore with this gal, etc. I feel that these players miss the point of a sandbox MMORPG, and wonder if they really like this genre at all. If not mitigated somewhat, this leads to isolated, independent gameplay, devoid of community.
3. Dr. Jekyll and Mr. Hyde: it's the guy who wants to play both sides of the fence. These players want to have multiple characters so that they can be Bob the Respected on one character, and then a griefer, spy, or general pain in the butt on another. You know these guys, they want cheap, throwaway characters so that they can engage in whatever, and have it not effect their "main". Again, this isn't good for the genre, and if not mitigated it leads to lots of griefing and obnoxious behavior.
