Sure, a lot of the complaints are about not being able to have your role 100% of the time. I miss that too, I'm a very casual gamer, I'm good at a select few things and if I'm pigeonholed into something I don't really want to do because of this new system, then I'm not enjoying the game, and I'd might as well not play.
I've seen a fair few posts about people like me who loved almost every aspect of team builder. Maybe riot doesn't care about us casuals or whatever, or maybe there's just not enough of us for them to be able to cater to us like they do the larger majority of their playerbase, but for someone who plays this game casually, team builder was sort of the dream. You can play who you want, where you want, you can choose what team you play with, and if you don't want to play with them, you absolutely don't have to. Leave the team and find a new one shortly, without any punishment. Maybe most people miss only the selfish parts, but for me, I have no interest playing rift when I can't choose who I get to play with. People complained of long queue times in TB, but I personally never found them to be long enough to dissuade me from playing it, and the teams I got were generally 100% more pleasant, because everyone was doing what they wanted.
The type of people I encountered in TB and the kind I've encountered in draft pick in the past are an entirely different group of people, and it's painfully obvious now that draft is my only choice besides blind pick. TB was a very stress free way to play the game, and as someone who gets stressed quite easily, I appreciated that a lot. I think people forget that not everyone wants to be great at every role, or wants to be super competitive about it, and trade bans and counterpick and all that, but that's essentially what they're telling people they have to do if they want to continue enjoying the game. Regardless, it's a moot point, and I'll either adjust to this new way, or stop playing the game entirely, because I've yet to have a positive experience in the new champ select. I'll keep trying, because I do love the game, it's the people that I have to play with sometimes that ruin it for me, and like I said, TB and draft pick offer an entirely different set of people when you're playing. At least that's been my experience.