That removal encourages people to gravitate to one specific GC and solo queue together under a countdown, which can total up to 12 to 20 people being in the same team all in voice comms. Re-adding 8 man premades will encourage people to group up in 8 again, and we all know premade queues put you in a random GC, not a set one like solo queue with freelancer off does, which means the 3 potential premades would most likely not be on the same team.

There is literally no room for arguement against the idea of 8 man premades being bad at the current state of 8v8v8 being removed.