First time I think we'd agree on something lol.
First, you are seeing more healers and tanks, because there are more players now. I know plenty of people that quit healing because of clerics stance changes, I know more healers that quit because of MP homogenization. I also know a lot of poor healers that have stuck to if with a false sense of hope that it will get better. I know ALOT of tanks that quit when stance dancing was turned to emnity on / emnity off. Cause lets be real stance dancing wasn't actually removed. we still have to dance between emnity on/ emnity off mode, it was just made less impactful as a whole. Why would a tank want to play a 4 button dps with emnity on / emnity off mode and a couple defensive CDs when they can just play a dps. I really miss emnity mechanics, it truely gave the game an extra layer IMO. You see more summoners cause it was reworked into what a lot of players wanted. I don't see many of them that have stuck with it so far. Summoner was a step in the right direction, but a bigger step in the wrong direction. I think it can be fleshed out into something awesome, but not this expansion and not with these devs. In the end, you are really just seeing what you want to see, not what is really happening.
Now you are right more buttons doesn't always mean more complex, but it also depends on what those buttons do. Remember my stance dance thing, it was one less button but it made a huge difference in tank identity and a huge cut to over all game play for tanks specifically. So yes you are right more buttons does not matter no one will argue this game just needs more buttons like why can't my combo be 18 hits instead of 3. It is more about what those buttons do and how they function in the class specifically that matters. Many of the buttons that have been getting cut have been very vital to many classes identity as a whole and that is where the problem lies. So stop talking about the amount of buttons that is not what the complaints are about, it's about the specific buttons. Maybe take a literature class, or something to help your reading comprehension during your break from telling us more buttons doesn't mean more complex.