It seems to me that Yamato's tool box has more tools in it than Andromeda, and yes, I did note that Yamato's guns are bigger and of a different energy type as as well. What's really interesting is the factory that has been built inside Yamato, I'm betting it's a spare parts replicating factory, possibly using some kind of Star Trek like replicating technology.
The whole Wave Motion gun agreement to me is a bunch of idealistic, naive bullshit. If it were me, I would have made that promise with my fingers crossed behind my back. I don't blame the earth government one damned bit. It's a nasty world out there, there's bound to be belligerent people out there with very powerful, similar weapons out there. And without the WMG technology, earth would be left pissing in the wind facing similar weapons with nothing to counter it.
In other words Sanada is the only one amongst the crew with a rational, logical take on reality. Good for him I say, and damned lucky for rest of the crew and by extension, earth as well, whether anyone else realizes it or not.
***EDIT*** It seems that Yamato's toolbox isn't bigger than Andromeda's after all: Two-wheeled wave wave implosion radiator (commonly known as a diffuse wave gun) 40.6 centimeters tripletary convergence Compression type shockwave turret × 4 unitsRapid fire torpedo launch tube x 4 gatesGravity piece spread launcher × 4 units Small torpedo launch tube × 8 gate Four consecutive anti-ship grenade projectors x 2Subspace torpedo launcher x 4 units Short torpedo launch tube Multiply mounted missile launcher x 16 unitsProtection Shockfield Gun × 3 units Six side-by-side ray guns for proximity battle x 2 units Aircraft pulsed laser turret × 4 Diffusion type anti-aircraft pulse laser turret x 1 Mounting machine / equipped boat 1 style space battle attack <Cosmo Tiger II> or 99 Expression space battle attack machine <Cosmo Falcon> × 36 aircraft100 type spatial reconnaissance aircraft x 2 Space general purpose transport machine SC 97 <Cosmo Segal> × 2 machine Two internal boats