Just finished the game (on PC I might add), and personally I think the TMD use was balanced quite nicely against the shooty gameplay. Sure the stuff you could use your TMD on was fairly limited, but in combat it made a handy device (although the ageing mechanic guzzles a bit too much E99 early in the game. later that changes), but once you get Deadlock it becomes super useful. The bubble really makes it easier to deal with fast enemies and combined with Impulse you can really make a mess of most of them. Add the gravity gun function and "incredible machine" style hilarity ensues as you launch exploding barrels and such into the time hole before collapsing it.
As for the weaponry, I loved the Seeker, and while I could understand that they didn't want us to have this weapon all the time, having it so rarely was a bit of a let-down, manual controlled bullets are awesome.
As the game progressed though my weapon loadout of choice was the shotgun (which thanks to it's pretty amazing rate of fire feels awesome from the get-go) and the Autocannon (exactly what it says on the tin).
The spiker, while awesome in concept felt weak, the sniper rifle was too situational and the assault rifle just didn't pack enough punch, especially compared to the Autocannon & shotgun.
You could say the Valkyrie's range was an advantage, but you rarely needed it, most stuff happened up close anyway.
The pistol is handy, but could have been more I feel.
also, did anyone notice how dramatically they changed the opening of the game compared to some of the earlier story trailers? The original opening I saw was the player crashing their spyplane on a flyby of the island after odd stuff was reported, and now you're a marine flying in by chopper (and crashing).
~War beckons, and I answer~