User blog comment:USARMP/Ninjas in Mass Effect/@comment-4237253-20120414044902/@comment-1388547-20120414152746

Multiplayer Vanguards aside, Charge seems to a very uncommon ability on the ME 'verse. In single-player, we've only seen Vanguard Shepard and Tela Vasir use it. (I seem to recall seeing a reference to somebody using it in ME: Deception, as well, but I've avoided reading that book because of how awful it apparently is.) Perhaps it takes a very strong biotic? Also, from a gameplay perspective giving Phantoms Charge would be horribly hard for the player to deal with.

At a guess, Cerberus was going for speed and agility with the Phantoms. The other troops don't have biotic barriers because (a) biotic recruits are uncommon and (b) it's cheaper to give troops conventional shields and protective gear. Even an organization like Cerberus has a limit to its resources, and regular troopers are good enough for most sub-N7 opposition.