Biotic Charge and Poison Strike both work perfectly fine the way they are. What you are describing is essentially Poison Strike which will hopefully be an alternative option for vanguards in ME:A and works much as you describe.
Poison Strike is like a cross between Biotic Charge and Reave that lets you direct your movement rather than have you target a specific enemy directly: it primes up to 3+ targets in your path for poison damage and detonates multiple biotic explosions. It's all about the damage over time not the impact - of which there is non to speak of because you go through your targets over to the other side. Without impact you cannot recharge your barrier. Always take damage not range and use it constantly in combination with teleport dodge to avoid damage and dish it out because with this power If your not moving, you're dying. Although with the Biotic Focus power you can recharge your barrier when necessary and it will give you 25 p/c damage reduction when active on the Cabal. At level 6 PS's damage over time is quite strong but it only really shines when you add in nightshade blade poison damage over time as well, which will also immobilize lower tier targets including phantoms. It's actually much better than charge for bosses because banshees, phantoms, brutes, etc. 'can't touch this' and the combined damage over time is stronger than the direct damage output of a couple of charges. Because it counts as a biotic power you can get the bonuses from warp ammo.
I use it all the time on platinum on smaller maps like Glacier and we always extract because being able to direct your charge through walls and between floors you can revive somebody anywhere on the map within about 5 seconds. I use an SMG despite not actually taking the stabilization passives just so I can use a power amplifier V for extra damage and use the grenade like a shotgun. Obviously Grenade Gear V is essential on this kit. I tried just taking 3 fitness in exchange for more passive power damage but it just wasn't durable enough so I would suggest taking fitness to four (1200 shields) so you can use an additional Power Amplifier III-IV armor gear instead of taking cyclonic gear which will be necessary on platinum for the extra dps. You can mod it into singleplayer if you are familiar with coalesced editing on pc.
Suggested build:
http://kalence.drupa...!311!411!!80855