Its nearing 2016 and still no global unlock on champions for ARAM.

Why?

It would take away some stagnation of seeing huge poke/all-in champs every single game from the ARAM only accounts.

It would help new players experience more champions easily.

Is there really a reason not to? (I'd seriously like a Red's response on this. It seems like the logical direction to take ARAM.)

Increase re-roll cap to 3 if you have to, but even without, there's literally no negative to this change outside of "I don't want to play x champion(s)" which shouldn't even be a serious factor in ARAM.