User blog comment:LilyheartsLightning/Citadel and Reckoning DLC announced/@comment-24174486-20130225174706/@comment-4721065-20130227105259

Technically, the shields have had limited effectiveness against energy attacks since ME1: look at Phasic Rounds and Proton Rounds, neither of which can completely bypass the shields.

Regarding the melee/slow-moving attacks, I would say that though the adjustment is present but very,very limited, because let's face it, pure kinetic energy of varren bite is much smaller than that of a burst from assault rifle, yet the latter are, if anything, less effective against shields. As such, I would say that against such slow-moving attacks shields can only function at ~5% of their capability, because otherwise you would have varren biting and clawing at your shields for five minutes straight before they would finally be able to do something. As such, the omni-bow would make sense, particularly given that it has explosive tips and is designed like a crossbow, rather than British longbow as in Crysis.

Finally, I would say that the best use for melee weapons in such futuristic universes would be either in regular ambush OR if you have run out of ammo, one would hide behind cover and not come out until their enemy comes into melee range. Simple, effective, very frustrating for the players if done badly.