Yeah there are a few problems I have with so many new champs. I can't deny that it is exciting having a new champ out and after a while of nothing new, it gets a bit boring but nonetheless it seems to me that although Riot has been adding so many new champs, they haven't been changing some things. I agree, there have been champions dominating the meta since they have been released, of for seasons on end have not been a bad pick. Some champions just go unnoticed, even newer ones like Aatrox and Quinn are rather underplayed in my experience. They aren't bad, they just are not as reliable as some champs and they wouldn't be that hard to fix, as they are already good, but they go unnoticed. One thing that comes with more champions to me would seem like we need more bans. It seems to me just that 5 bans makes more sense, especially given so many new champions, but I won't go too far into it. Another thing is that as new champs get these different kits, they can definitely outshine older champs with more binary or lackluster kits, and some older champs have been changed, but just kinda find it harder to contend with things like double passives, full hp shields, blocks all projectiles, etc.
I'm not angry, but the rest of this seems like a rant and is kind of irrelevant. Given more time i would go into why I think Quinn is good and how to make her played more, etc, (not relevant.)
One problem I find with balancing champs is that mobility is sort of a given. You have Janna, who should be mobile and has ways to run away easily, but then you have champions like Lee sin who have lots of mobility and then dashes. Then there is Kogmaw, by no means a mobile champ (makes sense) but not only does he have no escapes, he also has 325 base movespeed, whereas some champs begin with 350. Another thing about Aatrox is that he is an example of what I think is a more balanced champ. His q is decent, and a gap closer, so necessary for him to get close to the enemy. However, where they do right by Aatrox, they do wrong by so many of the meta ad casters. Aatrox's q is gated by long cooldown and costs a resource, although that doesn't mean much. Many of the meta "op" champions that I hate to face such as zed, riven, yasuo, lee sin, they are hardly gated by cooldowns and not really gated by resource, zed and lee sin (don't even pretend to say that Yasuo has to manage his flow.) they use energy, but leesin's passive automatically lets him use another ability if he autoattacks, because his abilities cost 30 energy. Zed is kind of better. Sorry for the "rant," this is just some of what I think is wrong wi