I'm all for careful movement and all that too. I tend to move carefully and still have the occasional what I'd consider to be lucky reaction shot and whatnot take someone out. I kind of just accept that in conflict there are going to be losses and it's unrealistic to expect otherwise, and don't overdo the caution to keep my mission lengths reasonable.
I think a big difference is map design and alien deployment. In new XCOM the maps are designed to be less about hide and seek (compared to say, Silent Storm at the opposite end of the spectrum where tediously looking for that last machine gun wielding dude in a closet can take forever). The "pod" thing and how aliens scatter to cover in XCOM means you usually deal with succinct battles of a tight scope - as someone else said, little tactical puzzles, where how you move on the large scale matters but the little battles are what really count and it's more about resolving those battles than meticulously scouring maps for that one straggler. You still have to move around the map carefully (mostly to avoid popping too many pods at once since that's very bad) but it's more about exposing the next battle area than it is to carefully avoid that one hidden mob from wrecking someone.
The pod thing in XCOM if you haven't played it enough is basically this. When you encounter aliens they are usually in groups that are just chilling, and as soon as you encounter them they scatter, usually into cover - THEN combat begins with your people acting first. So you almost never get the drop on them and they don't get the drop on you, and assuming you're moving your people from cover to cover and they scatter to cover, both sides basically start in decent locations and it's kind of a fair fight - which in some ways is cool, and in some ways it's kind of goofy, but it does do away with the "one dude in a closet with a machine gun" offing someone blindly thing.
In Xenonauts the aliens can seemingly be anywhere so there's always that chance of running in to one where you least expect it - which is very different from new XCOM.
Side note - Long War mod for XCOM makes the tactical much better IMO and shows how good that type of system can be (although the overall kick in the nuts difficulty of LW is a bit much for my tastes and other people I know who've tried it couldn't take it at all). LW still has the pod thing but mixes in more patrolling aliens and calls for help that can spice up battles into the realms of super nasty.