It's easy because you can do VOG as a lvl 32 with a team of 30-32 people. Before the DLC it was hard to find lvl 30 players wiling to take lower lvl players through VOG hard mode. Also, I'd guess Bungie increased drop rates on it, I've played HM 4 times in the last 2 weeks and got Vex twice, and the other two times someone else on my fire team got it.

I dont completely. You should be able to bring in your new gear with its perks, but the raid should only recognize you as lvl 30 and not grant you any additional armor or damage bonuses.