Yeah, I was wondering this myself. The squishy nature of MM's will mean we're useless in PVP - unless somehow we engage without being visible (hide behind a chimney pot perhaps 
).
Stealth is fine, as it means you still impart Supremacy to your henches. Invisibility will cut off any PBAoE buffs including Supremacy to them.
Henchman can still follow you, and you can still order them when stealthed.
so we can be invisilbe while our pets attack things?.. was wondering whether it was worth to get the dark stealth power and powr pool stealth.. might be handy. I mean afterall u cant get hurt if you cant be seen.
I was thinking along similar lines with teleport. Send my minions off to attack and then teleport out of there. Wait for the pets to get killed, resummon and repeat. Could work quite well against some of the squishier AT's.
A large part of staying alive in PvP is mobility. Teleport is great, as it is almost impossible for someone to follow you, and works even when immobilised. Superspeed is also a good one, and being a mastermind, you can let the pets do all the work, so the speed doesn't get supressed. Flight is handy too - just go straight up and a lot of people won't be able to follow you.
IN MEMORIUM OF GAYBABY
CRUELY TAKEN FROM THIS WORLD WHILE SO YOUNG
I was wondering if any beta MM's have had experience of the stealth power pool.
I read that MM,s are often quickly disposed of in PvP and though maybe stealth/invis/phase shift might help out.
I notice with my stalker though that Mission NPC's that are supposed to follow me cant seem to when I'm hidden, if our pets do this too then its obviously going tobe a non starter.