well, to realy decide that u should post some details on what could be used with a historical then.
If u only allow what was around there, im afraid it would get a realy boring campaign with same decks both sides.
Personally i dont want a campaign that gets played with only inf probe decks.
I would for example say restrict doctrines like Blitz, Deep Op, maski etc. those who give a big advantage to attacker and maybe inf Probe to give the general doctrines and maybe even massiv attack a chance to get played without to much fear
Doctrines like Combined Arms, Air support etc allow for better defense layouts especially if we restrict the units to what was available during that time period (So no panther or IS-2 etc) But we still need to keep the balance over historical accuracy.