It was never a secret that ARAM had huge balance issues; this was known all since the mode came to life, way before the Howling Abyss. People used to play ARAM on SR in customs before, and had been begging for an official map to deal with trolls that went to the jungle/sidelanes or people leaving the game without repercussions because of the champion they got. If they scrap Howling Abyss, people will just go back to this, and no one wants that.
ARAM is inherently imbalanced since teamfight prowess and damage consistency are the two main champion characteristics that bear any weight in the mode, and safety being a strong runner-up. They alleviated some (read: a lot) of the imbalance with the snowball summoner spell, but ARAM is ARAM: a chaotic, imbalanced, non-serious damage- and cc-orgy. Some games are less fun than others, but no amount of number tweaking will fix that.