I think they just need to deter people from dodging in ARAM more. There's no reason to dodge unless you have someone trolling. Don't like your champ and out of rerolls and no one wants to trade? Too bad, it's ALL RANDOM so don't play the game mode if you're not willing to accept whatever you get.
I've only dodged once for ARAM (played about 300). My main (jinx) was given to someone else, i asked to trade and was declined, then watched as jinx proceeded to be traded from one ally to the next, until all 4 players had had her and traded her. If my allies were willing to troll me like that in champion select (you all traded her so no one wanted her, why not let the main use her) i had no desire to play with them.
Otherwise, i play whoever I'm assigned. I rarely reroll, only on the very rare occasion where i get assigned a free week champion that i have no desire of ever playing and no idea how to play. i find it very frustrating when people dodge, and often once someone dodges i see 2 or more dodges in a row.
ARAM should track how frequently you dodge and prevent you from playing the mode at all if it determines you dodge too frequently... (at least temporarily, could warn you too ) .