Depends on if you want to keep it "pure summoners rift" but faster or not. If you add too much it becomes a half baked LTO game mode.
Also as a primarily ARAM player, and as someone who has been playing since almost launch on league in general, be very careful with the adjusted nerfs and buffs please. Unless someone becomes an absolute menace it feels really bad to pick up a favorite champion (Sivir, Ashe, Teemo, etc) only to find out they're hyper nerfed, although obviously makes sense in ARAM. On the flip side, you don't want to bait new players into enjoying a champ only for them to find out how much more buffed they are than normal (Akali, LeBlanc, etc)
I can speak a lot on this, but those are the absolute top thoughts I can think of.
Currently trying to stay close to being able to call it a Summoner's Rift experience rather than some other game mode. Hear you on balance changes that are too significant being warping, overall it's looking like we'll just need small tweaks since the characters are already designed and balanced for base SR as opposed to something like ARAM that puts really different demands on every champion's kit to perform equally.