The starting gear doesn't bother me really. At least for ground forces simpler gear is in general better than a more complicated parallel, even if they were somewhat more effective. For instance, you could swap out all your forces' paper maps for PDAs, but what happens when your infantry gets stuck out on the front lines for a week or more without a place to charge the PDAs? Same with your firearms, low maintenance guns means that your soldiers need fewer supplies to keep fighting.
On an artistic note, it also provides a reasonably clear indication of whose tech is whose. Human tech is more angular and boxy and dull colored, alien tech is curvy and bright or has lights, and the union of the two has some of both. Including human gear that has the smooth, sleek design that a lot of people think of as futuristic would mess with the motif.
There are some things in the game that gives me pause. Most of it is stuff that is in development or has to do with needing more content. Like the harvester crews that huddle together in a lower front room when you stand a soldier beside its hull. And when you shoot down a craft over Antarctica the map is very much like the ones in (the populated sections of) Russia, and the women are wearing short skirts (not a single penguin or polar bear to see, either). I'm fairly certain I saw the topless islander woman on a Saudi Arabia map, too. Also, while I understand the point of merging nations together in the game, I find most of them hilarious when I think about it.
One thing I would say is off is the first encounter story. I get that ETs' strategies would not be our own, and that they strike in waves; but the initial urban attack sounds like it was heavier than anything I saw in the first year (standard difficulty, but still). It would seem like the recon missions would be worrisome enough that they would form PHALANX. It would also explain the apparent ambivalence at the start of the game; and as the alien assault grows in strength the nations would be willing to cough up more funding so long as you were protecting them effectively.
Willing suspension of disbelief is fairly easy to keep up so long as there's no huge shark jumping involved. Like if it turned out that the aliens were led by Elvis and the final mission had him as a boss riding a rainbow triceratops singing "Another One Bites the Dust" as he fires his dual belt fed particle cannons.