Maybe it's to keep Xbox users from being butthurt about PC players getting a feature they don't. It's "their" franchise, after all, "best" on their platform.
I saw a post about the lack of text chat on the BioWare forums the other day, and it was ridiculed from the start because "you wouldn't have time to type, anyway".
All a vanguard really needs is fully upgraded biotic charge and all the cooldown reducing traits you can muster. Just spam charge and you'll be almost completely invulnerable in bronze and the first half of a a silver match. Charging anything in gold is suicide. An asari vanguard has the bonus of being able to incapacitate phantoms with stasis, which turns Cerberus into a shooting gallery. However, you end up accidentally kill stealing a lot, and you constantly risk the charge glitch (charging and dying at the same time: does not compute) that will make your character spaz out uselessly for the remainder of the match. Both tend to annoy the other players.
I love vanguards, though, because they have the ability to detonate my biotic explosions!