The main thing that causes problems during the respec is not realizing that more than any other encounter I have seen you need balance. Every archtype is VERY good to have in the fight and you likely will need some of each to complete it.
Originally we tried with a tank 3 defenders of various types and a controller. We did fine but we just did not have the dps needed to take the bosses out fast enough. We wound up advertising for a scrapper and a blaster when we got them the event was a joke. People were actually getting a lil bored cause we would clear the waves so fast that we were sitting waiting for the next reactor wave to spawn.
If you go in there with an unbalanced group you likely will die horribly and often.
Honestly I think more missions and taskforces should be balanced like it as it really makes all AT shine for what they do for the group.
kaid