More big ARAM changes are coming with Patch 7.10
There were some pretty big changes to League of Legends' ARAMs in Patch 7.8, and some of those changes flopped a little bit. That's why Patch 7.10 is pushing out more ARAM changes to polish things off and correct the mistakes from the last round of updates, according to the official patch notes.
One of the most significant changes from Patch 7.8's ARAM update was the mana regeneration buff. With mana regen being hiked up, mages are now able to sling spells a lot more often and with a lot less risk. Because of that, melee champions have been suffering quite a bit. That wouldn't be as much of an issue if each team had an even amount of mages and melee champs, but this is ARAM, where teams are decided based on as much RNG as possible, and you might just go up against a team of five mages with Master Yi, Udyr, Hecarim... you get the point.
To help out melee champs, they're all getting ten more magic resist when playing on the Howling Abyss map (that's where ARAMs take place).
Loot for days
In 7.8, the level of gold you earn passively every second was buffed, and minions began dropping gold just for being near you when they die. Apparently, that wasn't enough, because Riot is buffing the gold per second and gold on nearby minion deaths. More gold means more items, and more items means more damage.
Super minions are way too super
The last large update to ARAMs in 7.8 was to the super minions that spawn when you destroy the enemy Inhibitor. There's no better way to say it—they were jacked up. Super minions had their armor and damage nearly tripled, and they grant nearby allies a big boost to movement speed. Oh, and there's more of them. A lot more of them.
To quell the looming threat of super minions emerging from the Howling Abyss to take over the rest of the known world, they're being dialed back a bit. A super minion won't spawn in the first wave after killing the Inhibitor, and their armor is being lowered a bit. Also, they're getting some magic resist added to their stats, because they had none until now. It isn't much, though. The movement speed buff will no longer be active while the minion is in combat, and the Inhibitor respawns faster, so super minions are a bit less oppressive.
These clean-up changes should be enough to swat down the bigger issues with the ARAM update in Patch 7.8. The patch goes live tomorrow morning, so if you want to try playing in an ARAM where super minions are all-powerful titans, you can. They're still pretty strong though, so be careful.