Sounds nice, especially "Hire a Level Designer", which would solve some of the replayability problems without costing near as much as a new tileset (would love to have new tilesets though, and hopefuly the Kickstarter gets overfunded to allow everything).
What about combat mechanics though, walking crouched/crawling/sprinting + smoke grenades? They'd allow for far more varied tactics, and would be even easier to add if the level designer stretch goal is also achieved. Basically, anything that allow for a more complex/varied gameplay, for the player but also for the AI (mission design).
And I do feel women soldiers and Linux/Mac are important, even for backers who only care about the gameplay. They're crucial to make all players feel accepted by Xenonauts' community, especially after reading some of the offputing comments from the existing playerbase (I've been following the forums since the beginning, and only with the Kickstarter did I feel at ease enough to subscribe to the forums).
20-30 new portraits + one (one!) basic armor artwork can hardly be considered as endangering the budget when you're offering 50 backers (90 if you include higher tiers) their own portrait for the 50$ difference from the lower 150$ tier. I must be dense and misunderstanding a lot, because it makes it seem like all this fuss about the high cost of adding female soldiers was because nobody at GHI valued making female players feeling welcome worth 20x50=$1000 cost (plus what, 200$ tops for a basic armor modification, and there's no money to fund another tier or armor tweaking?), which is atrocious seen from the userbase point of view.
That's probably part of what upset gamers - the Kickstarter and your explanations make people realise that drawing a new portrait is dirt cheap (IIRC you said it would be $30-$40 to outsource each one), but everybody at GHI or among the forum oldtimers seemed to agree it would be a waste to spend even such a low amount when the face being drawn would be that of a woman (because women, unlike men, aren't worth even 40$ to Xenonauts players)?
You're a man, but ask yourself this question: if you had a daugther, would you be confortable letting her play a game reinforcing the idea that only men are valuable, especially when it comes to important jobs like saving the human species? How can she identify to positive models if the only positive ones are of men (because "they" can do the ultimate sacrifice, unlile her)?
I'm not saying it reflects reality, but it reflects the perception potential supporters have been given. And that external point of view would also want to support your game.