Air vents should be in Xcom

I'm pretty obsessed with Xcom, and I keep thinking of other ways that would improve upon it.  Xcom Long War goes a long way towards that, but I do feel it misses a point when each class is basically recycled abilities with a handful of unique ones to make sure there is still definition between them.

But other things I think about are the covert missions, and how sub classing would be a fun addition to that.  Sure you have your gene mods and can use them to their advantage in mission, but I would like to play out some part of that covert mission using a unique set of skills.  This is pretty much inspired by Splinter Cell, which I have been obsessively watching videos of lately, and wondered what a single character moving about the secret EXALT facilities would've been like, directly controlling their infiltration and their actions, possibly changing the effect of the eventual battle with EXALT in the end by sabotaging communications or the reinforcements themselves, maybe collecting further intel on their whereabouts or striking at further hidden bases.

And you would have your subclass abilities providing bonuses like "sneak peek: cannot be seen at corners unless theyve shot or are on overwatch," or "Monkey Grip: able to hand over ledges or on certain wall surfaces", or "Execution: able to melee kill living enemies with less than 8/14 health instantly."  Maybe that's a bit much, but it's an idea.