GMs have gotten stale and I do not find them exciting anymore. I propose adding the third champion to each faction to spice things up, here's my recommendations.
Scorn: has overload and unstop: easy call here adding a sniper champion is the play here. Add Barrier Raiders
Taken: overload and unstop: let's make this one annoying. Barrier Captain this changes the dynamic of the normal personality of Barrier champions
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Cabal: Barrier and unstop: this one has a couple that could fit the bill. Think the evasiveness of a Psion would be perfect.
Hive: Barrier unstop: this one's so easy it's not even funny. Insert overload wizards into the game.
Fallen: Barrier overload: only 1 enemy works for this... unstoppable heavy shank.
Vex: Barrier overload: no one wants this onslaught. Easy call here with pull your hair out frustration. Add unstoppable wyverns.
Warden of Nothing is the only GM to add all of the Champions at once due to Vex/Cabal working together in the strike at the same time as a prison riot.