If you remove dominion use those extra resources to improve the new player experience. . .

My thought on how this could be done:

Tier 1 and 2 runes are a joke. Remove them, keep only tier 3 runes. Offer new players an IP discount for runes based off their level. Add a new tutorial, stop telling people to build thornmail on Ashe. Teach new players the different roles and how to navigate the suggested items page. Offer IP boots to new accounts that group with friends to encourage teamwork, since dynamic queue is heavily encouraging 5 man pre-mades. Add a "beginner" queue that only allows accounts under level 10. This would provide an environment for new players to learn the game and smurfs can head straight to the normal draft. [Disable the banning phase??? New people should have access to try all the champions] Give new players 10 mastery points to start off, unlocking 1 new mastery each level after 10. This way it's an even playing field in the "beginner" queue. Tone down jungle creeps in this queue to compensate for level differential from normal draft. Give new players 6300 IP to start so when they like a champ on the free week it isn't immediately unavailable the next week, that is hard and confusing to new players. Alternatively, make a handful of champions permanently free. Offer a reward to accounts that make it to level 30 with good behavior to encourage sportsmanship in the game, as well as teach players how to deal with toxicity at an early stage (and promote smurfs to use good attitude as well).