IMO Switch out as a move is NOT busted.
At first I thought it would be busted as well (the trailer).
We will have to see when the game comes out.
I used trainer myself (a little) during E3 and got opinions from others.
Generally, I hear the experienced veterans say it's very good.
But most took a conservative "we shall see" response and a good amount said it's not broken.
When I mentioned if it is comparable to Brawl Olimar's whistle spam, people said it does not even hold a candle to it.
I asked this to illicit a response. Yes, I know how to use Brawl Olimar and his Down B is busted.
I did hear a lot of "OMG it's busted" but I think these people are grossly overestimating its potential.
It is an extrememly good move, but it's not something to be spammed 24/7 with little consequence.
In the end, I'm not sure if this could be considered "broken", but it is very promising and very unique.
If you look at the youtube videos of ultimate trainer, switch out is broken comments are not uncommon.
In some situations its extrememly useful such as baiting in advantage&neutral and as a psuedo airdodge/spotdodge in disadvantage.
PKMN trainer will be somewhat different from his brawl iteration with all the buffs. Especially with all the Smash 4 changes of Zard coming over.