Yeah I agree with all of that. The thing is a lot of people thought A2 was going to behave like just another frontloaded sequel, and that clearly did not happen. So I don't know how you can call the legs "normal" on this movie when it has surprised most people on this forum.
As for the running time, well it's hard to say JC made the wrong call considering the success the movie is having. So I don't know if we'll see the same thing for A3, but Cameron likes to take his time for sure. I think the only thing dragging down A2, and why maybe it felt long to some people, is that the movie had to introduce a lot of new characters. Now that all the pieces are in place, I think A3 is going to be even better.