Well, I'm glad you're having a good time reading what we scrubs post on the forums
All I know is there are characters that die when Reapers sneeze on them, and then there's Drell who dies if he himself sneezes. Maybe it wouldn't be so bad if there was a Drell soldier who could focus on weapon damage while staying in cover, but the Drell characters that we have are pretty weird.
You mean like the Drell infiltrator.
Also, if a Reaper attempts to sneeze on a Drell, said Drell merely sidesteps, and is about 20 metres away before anything can happen.
But seriously though. Go have a look at the Drell passives. Not just movement speed, but the weapon, power and headshot damage bonuses. They're among the best in the game, alongside other top tier characters like the Turian Soldier. Biotic Charge adds to that damage as well as survivability, as does Tactical Cloak. Cluster Grenades are a strong contender for being one of the best grenades in the game, and when you remember that they can detonate bioitic explosions (and have an evolution which adds to this damage significantly) and that Reave is an AoE power...can you say "killstreaks in a can"? The Infiltrator also has Recon Mine on a three second cooldown.
Barriers or shields really don't matter that much, because you should be using soft cover and situational awareness to avoid getting caught in situations where enemies can unload on you. Of course a Drell will die quickly out in the open...but on the higher difficulties, practically everything gets shredded out in the open, regardless of shields and health. Arguably, on host, speed is much more useful than shields, and the Drell have that in abundance.