Vanguards are not melee, nor are the ranged. They are a hybrid of sorts. 10m's is our optimum range only closing to 4 to stockstrike and gut then back to 10m's. You can strafe away to 30 to deliver sticky grenades,assault plastique, and HIB's but then it's back to 10m's. Vanguards are very mobile. Most of the attacks are instant. So really with a vanguard you should be always moving between 30-4 m's depending on the situation.
Doesn't assault plastique have a 10m range?
Anyway, the VG is still awesome. You can strafe/kite melee players and burn them down in pvp. Pve is even more easy cause of the predictable mechanics of mobs. If you don't like it play a real ranged type, like GS, commando or operative.