I don't get it. When Season 4 went up, not only did melee weapons not get a damage increase like the ranged ones, but they also got hit by the nerf bat when it was changed so that they only dealt 50% damage through shields instead of a complete damage bypass like they used to. That pretty much quartered the damage they deal in comparison to the way ranged weapons work now, and to top it all off ranged weapons now get melee combos. I'm pretty sure they weren't thinking "let's make people want to never use melee weapons again", so what *were* they thinking over there when they did that?
I used to routinely switch between ranged and melee weapons during engagements on the ground, but now I've practically forgotten my melee weapons exist. It's rather... disturbing. So no, I don't think they're viable... unless you can get VERY creative with them or you're fighting the Borg with a player/BOff group that is sufficiently good at keeping you alive. When it comes to those two things, I believe there have already been a few examples of what you can do with them, but it still doesn't solve how "blunted" they've become DPS-wise.
Like I said... Unless you are fighting the Borg they are not useful. I am not sure what the idea was either... If the idea was to go for a more fully FPS feel then the Melee Weapons should have been used somewhat rarely but be utterly wicked. (ie. Halo, Gears of War, etc...) However, that is not the case so it seems as if they got a nerf for no apparent reason. They already had the downside that you had to hold your target still and be in their face. I figure with the Shotguns that is even more of a penalty these days but apparently Cryptic did not think so.