Group fly/teleport, I don't see as mandatory.
Taken from Posi:
Traveling With Henchmen
Henchmen can NOT travel across zone boundaries or into mission maps. You
must resummon them on the new map. If you get too far away from your
Henchmen on any given map, they will automatically resummon themselves
near you (keeping any buffs they had).
So if they do get out of range, they'll just appear next to you anyhow. Tactics/Assault and Vengence, I can well imagine being very useful for Masterminds. But I wouldn't take them in place of the primary upgrade henchmen powers, or the secondary buff powers.
CoV - Soundspeed (Son/Kin Cor)
CoH - Ms Taken (Storm/NRG Def) GoldenRock (Rock/Rock Tank)
WoW - Omikron (Druid) KappaOmikron (Shaman)