Agreed. And Oblivion was my favorite of the Elder Scrolls games. As Skyrim proved, however, better voice acting does not equal a better story or atmosphere (especially if all that variety in VA talent only leads to two lines per character).
Cheezy VA I feel would take away massively from the game. VA in general, perhaps not. This feels, however, like something that would have be planned much in advance of where the game is now. A voice here and there may be more feasible, or perhaps just for the lead scientist's briefs? Also consider the fact that the voice acting does limit modders later on, if they decide to add elements that normally would have been voice acted. I'm not necessarily arguing against voice acting in general, but it's probably a bit late to implement it on a significant scale. Everyone has their preferences, and while I would certainly laugh at a zany line every now and then, too much of that would turn me off personally. That's one reason I personally do not play the Warhammer games. I like the darker theme of Xenonauts, and the humor was done well in a way that did not detract from that. That last part is purely my opinion, of course.
I really like what Wyldfyre said as well regarding individualization/customization of the soldiers and vehicles and what not. The medals added were pretty cool, and it would nice if they gave some sort of bonus, but cosmetic differences (not to the fantastic scale of X-Com, of course; we do not want to lose Xenonauts' unique style) for veteran soldiers or vehicles would highly enhance the experience. Also I feel that would be a lot easier to implement than additional voice acting, and easier for modders to add to later on if that becomes plausible. The original post was spot on in highlighting how one of the areas Xenonauts 1 could have vastly improved was the ambiance (I agree with Coffee Potato about 3D modeled shell casings, but if it's not a hugeproject, maybe sprites or images could be used), especially with regards to the dropship sounds and dust and such things. Of course, these are minor things to be added if Chris is happy with the state of the gameplay.