10 bans
give every player full rune pages and every rune for free, and give the ability to edit runes in champion select. This isn't stuff that should be locked behind a grind. Its unsatisfying to buy a rune page over a new champion, and all that having rune pages locked behind 6300ip accomplishes is making new players less able to play a wide variety of champions
Give new players every 450 and 1350 ip champion for free, and unlock those champions for any old player that doesn't yet have them. While having good picks in every role isn't really a necessary thing anymore, everyone should still have them, and they should have a good variety of champions to play in each role.
Let people get demoted out of a Division 5 easier. Far too many players get misplaced, and because of the Division 5 safety nets, they never quite drop back to where they should be. It also makes climbing through any Division 5 worse than any other Division.
Let Gold players Decay again. If this is the tier that gets you rewards, the people in it should have to deserve it. Between this and the ability to be demoted easier, players will no longer be able to place Gold 5 or 4, stop playing ranked entirely, and still get their free skin.
Potentially remove promo series, or at least make them only for when you advance to the next tier. Promo series never really felt like they fit in a system where you are matched based on MMR, and the way that Promo series makes it so each division hardcaps at 0 and 100 LP is annoying (what I mean by this is that, if you are getting 20 lp per win, but are at 90 lp, 10 lp of your win will be essentially "wasted", whereas if promo series weren't a thing then winning at 90lp could just put you at 10 lp in the next division.)