I would be happy for them to just update the human weapons you start with to modern "real life" standards. IE more accurate Gls and RPGs, More accurate small arms and some new attachments/ammo for the weapons. Making them a bit more viable later in the game.
Examples.
None lethal rounds. Bean bag rounds for large bore weapons (shotguns, GLs)
AP rounds, Glaser etc
http://en.wikipedia.org/wiki/Armor-piercing_shot_and_shell /
http://www.dakotaammo.net/products/glaser/glaser.htmTasers
http://www.taser.com/products/military/Pages/default.aspxM203/Masterkey(shotgun) attachments
http://en.wikipedia.org/wiki/KAC_MasterkeyLaser sights for "Close" weapons Flash light attachments for almost everything
Accuracy of GL is slightly off IMO its about as good and 1st gen smooth bore grenade launchers IE Blurp guns
Accuracy of the rocket launcher is terrible ATM (2.2). In most open maps, I can't hit the side of a building consistently with a 30+ skill. I completely understand the idea that they aren't terribly accurate. I have used the AT4 and RPG7 in my military days and at 100 meters you can, with little skill, hit a 3 man bunker (roughly 10'/8'/4') most times. AT4 being the more accurate of the 2 IMO.
You could do a research heading for each weapon type. IE improved laser or Improved SMG These would allow attachments, lower tu costs or just add a little more damage or accuracy. IMO we should never not have something to research. Even if it's a minor improvement overall. I am not paying for those lab coat wearing geeks to stand around and wait for the next alien discovery to spark an idea.
Some new toys should come from the Civ side as well. This game plays out over years so why not have the Civs build a few new toys and let us improve/adapt them for Phalanx use. Seems the R&D output of earth comes to a stand still once the aliens attack.
For weapons the trees would look like this.
SMG ------\-------------------------------------------\
Flashlight AP ammo(-3 dmg reduction due to armor)
\ \
Laser sight (+3 user Acc, +2 TU ) Glazer ammo (+5 dmg)
\ \
Recoil suppression (-1 TU )
\
Bullpup config (+10 range, -0.2 spread)
\
Improved SMG (+3 user Acc, -1 TU, -0.3 spread, +15 range)
\
That is at least 6 new researches for a single weapon. These are only examples and the Values could be completly different
I could easily make a mock up of the tree for each weapon type if the devs or anyone else is interested.