I have tried it it, suddently reich - shogunate matches became much more interesting. And it does not clash with the fluff and rules as you can do that playing umtoma.
Not to mention fluff wise, Hoss does not even like Hermann, and would take the Nippon Accords as an opertunity to dispose of his rivial.
But on the other hand, my wife won a shogunate v. Reich game, but she was rolling a lot of 10s that night.
If it was ruled that both hoss and hermann cannot work together (much in the way of oksana and zorka) reich would be toned down, that rivalry is interesting to know!
A proposed Setup:
Hoss Harbringer with Command Pack, Drop Prescience for Helm of Diomedes or Mask
Iroh with combat pack, drop pistol for Elizabeth Bathory
Mizu with Stamina pack (in some games maybe wolf with combat pack to use him for overwatch)
Shin agent with Stamina (drop happo for call in the troops if a 2cp game)
Ashigaru with Combat Pack or Stamina, (if playing for 3 cp drop concentrated fire for XR-35 Bonus token) (if playing against reich combat for the grenade,)
On turn 1 change agent's pistol and first aid kit for ashigarus rifle and XR-35 ( with that she gets to roll 7 dice and repeat 2, thats around 5 sucesses per roll on average!) and extra resiliency for making the opponent reroll.
Use Iroh together with reichdoktor as soon as he gets 4 sucesses on an attack roll (quite often factoring in the 0s double wound and that you might spend a cp to enhance his combat ability, that roll with 2 sucesses for reichdoktor its 6 sucesses against 3 shock dice usually killing a hero or a trooper, the trick is that with elizabeth bathory he gets back to full health, in case you fail you have 1 or 2 medi kit to heal him.
Use Mizu for flags/objectives/domination circles, and heavily leverage shadowflash (keep her always near path limits)
Go kamikaze with the ashigaru once you spend his disposable equipment, so you get to reinforce with an extra rifle plus grenade or medi kit
Use Hoss mainly for out of path attacks and flags/objectives/domination