Why is it that there are units you never will use in BWii?

Solar Fighter- If it's not getting shot out of Anglo airspace, or plugged into a solar panel, you never see it.

Xylvanian Recon- You kill 4 of them in "Crack Squad", and that's the last you see of them. I really want to drive one ! But all recons are fun.

Frontier Battalestation- I didn't play the last game, so I've never seen, much less played as one!

The problems are two things. There could be way more co-op missions. Like one where both players are Xylvania, and both COs are involved. They could fight through two different streets of some random Tundran spin-off of a Russian WWII city, and link up to take an HQ. There could be more campaign missions, also. I'd like to see every campaign with 5 to 6 missions, including flashbacks. I guess we'll have to wait for Battalion Wars 3...

BTW, if I'm wrong about never getting to play as one of those, please correct me!

I hate it when I want to drive it but I cant. I REALLY REALLY want to fly a Solar Jet! They look SO COOL!

Maybe you can.
Maybe if you destroyed all the units at the title screen, you unlock a bonus campainge. I've destroyed them all, and it made a beep as if it unlocked something.

lolz im gonna try XD