I agree that ARAM is now broken, it used to be just random fun, but good faith is no more in that mode, people create smurf accounts with only god tier ARAM champions, premades abuse the switch-reroll system, etc... so Riot should take care of this and fix this mode in some ways.
Here is a thought, maybe they could balance the teams with some simple fixes to the matchmaking, going to write an example:
Divide the champions into 4 categories or tiers:
A: God ARAM tier (Fiddlesticks)
B: Fairly good
C: Fairly bad
D: Very Poor (Warwick)
Then you can balance the teams based on the average level of the team, so, for example, a team with two A´s, one B and one C cannot be paired with a team with only C´s and D´s. Since all the 10 champions are selected at the same time it would be real simple for them fixing the matchmaking that way.(They could limit the rerolls to do it even more fair)
Of course this is only a thought, and I am sure Riot will not do anything because, as said above, they only care about competitive play and competitive balance. We lost Dominion, we lost soloQ, and ARAM is less and less fun every day, so I do not expect it to be fixed, I am only stating that it will be very easy to do it, if they want.