simplely not true, i have done with guildmates in 16minutes and not a one of us use stealth.
i agree that going with guild helps as the chance of getting 2 sents with 13k hp each with a 11k guardian tank without a shield in a dps stance is really low and yes i seen groups like that for this flashpoint. if they don't get the fight 3rd time around start asking ur guild or friends for a replacement as 4th or 5th is just a waste. but i would highly suggest that anyone turning 50 alteast take a good monent to read up on this flashpoint before even thinking of que for this becuase the gear help but not as much as knowing they fights.
I did not know level 50 guardians with 11K HP existed! I guess there is a first time for everything!