But do they need to max out their core team asap?...

I admitedly started at a good time when a increased drop event was near, but disregarding that i have already gotten myself a really good team, with a few select units maxed in aff, the rest are handling things on their own even if they are not maxed on aff, i just have to adjust my tactics accordingly. I still haven't max affed my whole core team, but that doesn't matter because i selected some great ones to start with and they are managing most of it for me.

This is not about them rivaling anyone's team, it's about the fact that you don't need a full team of max affed units to do well on an event. I have 7 units max affed on DMM with 2-3 others at 20-50% and yet i got a PERFECT unit on the last star event. Heck, look at soranokira, his team lacks the 2 blacks i have and he also got a perfect unit on the last event.

Edit: Also during our last star event on nutaku i max affed two whole units.