Space Marines can still drop vortex grenades in 2nd Edition.
It just seems like 2nd would be more manageable, but I don't have a Rogue Trader book on hand to say for certain.
I know RT doesn't have some of the races people play now, and that would exclude certain people that only have Tyranids for instance.
Although, with early edition games there are lots fewer models on the board and probably all of us have enough tiny plastic men to field at least 2 whole armies. A 10 man tactical squad of space marines with no gear is 300 points.
In either edition, Tau, Dark Eldar and Necrons are out entirely. Squats are in.