The screen will be crowded with 6 pokemon. 2 on 2 was great, but 3 on 3 is a little overdoing it...
I think I'll send out Dialga, Palkia and Giratina all at once. But that's going to be overkill.
...Come to think of it, then there will be a new type of trainer, called "triplets", I guess...And maybe sisters...
...Imagine a double battle against a gym leaders and a Champion/E4 member, like the one in DPPt and HGSS, now becomes a triple battle against 2 gym leaders and a E4 member, or maybe 3 gym leaders...
I have to say, this new feature opens up a whole lot of new possibilities...