It's not impossible, but it's really annoying. For me, the annoying thing was the GI fight first each time. It seemed entirely up to luck if you would be allowed to get past him with the squad in good enough shape.
Most of the jedi I could figure out on the fly how to get past them. Only had to improve mods for fulcrim, just needed to be a bit faster to be able to get enough attacks in.
I think this event would be vastly improved just by GI having normal cooldowns, rather than allowed to just use that healing special that ability blocks your while team whenever he wants. He can lock you into doing just basics permanently, taking away player agency completely.
This faction did not need another reason for players to dislike it.