Most of the changes feel like are positive steps and if I'm being perfectly honest I'm glad the changes don't seem to completely change game fundamentals like some seasons past.
The one thing I'm wary of... is the dynamic map. I've never been a fan of that and I remember the original idea for the jungle plant spawns was for them to be randomized. This was eventually done away with because the RNG element would have been able to randomly give certain teams or players a large advantage. Personally I'm pretty much against anything random evolving in the game, even the elemental drakes were a bit much for me, (I would advocate for a set series or a randomized series chosen from a set on a game by game basis) but I do like what they've done to the game and the tweaks seem good here.
All of that aside, the Mountainous Rift (and to a much much lesser extent the infernal rift) seem to be heavily in favor of certain champions and team compositions. The other 2 while favoring maybe certain champions or with the brush pick compositions I feel can be played around in a better manner than the massive addition of terrain from the Mountainous Rift. Can you imagine a Quiyana in that game? An Amumu? The list goes on and I feel this has the potential to swing games heavily in favor of compositions or teams with specific champions, **specifically through no interaction of their own.**
I'm not against the dynamic terrain entirely but I feel it is important for the players within the game to have some impact upon how it is changed in order to benefit their chances of winning rather than receiving or losing an advantage on nothing more than a dice roll.
Throw up 4 targets after a drake kill that the winning team can basic attack one time in the pit to choose the next drake spawn.
Make it so that the specific person who secured the drake is the only one who can choose the next one so that within a contested situation if the opposing team kills the player who secured they no longer are able to choose and that is when it goes random.
It could even be a passing buff "Hand of the Drake" or something where the player toggles what spawns next and is therefore a high value target.
Those are just some poorly thought out and even worse written examples of providing agency over the drake spawns and therefore the future conditions of the map.
Give players and teams agency over how the map evolves if it is going to give specific team comps and champions significant advantages.