Thanks Chris, it's very useful to see the thinking behind some decisions. With that, I can make some more specific comments.
Very interesting, because I never got the impression that the intention was to give you energy weapons. My feeling was that converted weapons exist as a cheaply manufactured suboptimal solution, as in, you'd rather have lasers, but can use converted weapons to save money and workshop hours, at the expense of having less suitable weapons. Hence the high TU costs. So it might work to make that the niche - cheap, limited by alien ammo, rather powerful, a bit unwieldy.
If there's time, a solid pass on the economy would be on my wishlist. I often played X1 with a small personal mod that basically decreased Alloys and Alenium from missions, and increased the amounts required for production. It would be great to have a real resource economy. And a great opportunity to make landed UFOs more attractive by increasing
Alloy rewards from them. I would say in general, a good starting point is to assume X1 provided twice as many alloys as it should have.
Okay, I think that's a solid goal. I don't think it works well though. The early X-Com battles also took place on bigger maps, versus more aliens. The maps in Xenonauts are smaller, more concentrated, with more functional cover, and alien crews are smaller. With 10 soldiers, I don't find it to be more of a bloodbath, on the contrary, I am taking fewer losses because it's easier to fire a lot of bullets at each alien, or use other tactical options. This being another key difference versus the original X-Com, that game didn't have much weapon variety. Due to the weapon variety in Xenonauts, the two extra soldiers remove some tough planning choices (do I take a grenade launcher or another rifle? now I can have both!), which leads to less bloodbath.
Instead, I would say you can recapture the same idea by making losses likely across more early battles. You shouldn't be in highly upgraded gear on your third mission. This ties somewhat into the previous point with alloys, but also it's about tech requirements in general. Give players more missions with just the basic equipment, ensure slower introduction of lasers and other gear, and you'll recreate that desperate X-Com feeling differently.