I have a list of TTRPG topics, terms, and phrases that put me on edge immediately; "dissociated mechanics", "D&D 4e is just an MMO/Board Game", "rulings not rules", "Roll-playing". The visceral reaction I have is from a long history of reading and participating in (more the former, but still) design discussions and game reviews. I recently added a new one to the list: "You can't play the Avatar in Avatar Legends".
Now, that statement does have one thing going for it, which is that unlike "4e is an MMO", "You can't play the Avatar" is, strictly speaking, true. The problem is it's facile, and it shuts down discussion of the game's virtues in the same way the MMO canard does.
There are three reasons playing as the Avatar was left out of the game. The first is that the game spends a lot of time on setting details for time periods with a known Avatar. The game could probably have included notes on making your own Era or playing known characters in official Eras, but a decision against the latter isn't necessarily wrong, and the former may have required resources or licensor buy-in the publishers did not have.
The second reason is that having an Avatar creates a "main character" sort of dynamic, and the text indicates the designers actively wanted to avoid that. I don't think that would have been an insurmountable problem if there were some GMing advice on the subject, but it's an easy pitfall to trip into. I know that in my first D&D campaigns this was something I personally struggled with.
The last is the one that really gets my goat, and it's that the game isn't really designed to be about elemental martial arts - it's focused on the kind of character arcs seen in the show, how characters struggle between opposing ideals. All the most interesting mechanical bobs have to do with that tension. Bending is essentially just a single tag that informs description, and sort of interacts with some advancement options. The game probably could have stood to have a paragraph or two about how to run an Avatar if you absolutely had to, but it's trivial to actually do it - list the elements that they can bend and you're done. Even a hyper-formalized description that includes notes about element learning order and how to handle the Avatar state would take something on the order of five sentences.
I'm sympathetic to being a bit miffed that this requires a house rule, but between the game's obvious design focus on emulating the show's flow, the ease of adding it in, and the solid setting and gameplay reasons to pass it over it's maddening that it's the first thing that comes up in discussions about the game itself or about games that don't deliver on their premise.
