One For All in the Howling Abyss
I understand this idea completely and I know the fun that it can create because I was able to play it when it was available due to a bug in that recent patch.
Imo, get rid of it on Summoners Rift(SR). Here is why. This kind of game mode implies one of few things. Have lots of fun, and go balls to the walls! However, I feel like SR isn't the place for that. Having multiple lanes where all of the same champ will be in, or have just one singular lane (Howling Abyss) where the two teams can do that "quicker."
I have already had those game in One For All where we all just end up going mid anyways... If that is the case, why are we not playing in Howling Abyss.
What am I trying to say in all of this?
Simple.
This game mode is awesome and I do think it has a place in LoL, but I do not think that it has a place in SR. Move it to Howling Abyss or maybe even Twisted Treeline ;)
Have a good day (^_^)