If the majority of the players agree that more outdated units would fir better, then I'm all for putting tighter restrictions on what people can use in their armies. It's just that the army was supposed to be a side section of the CS, not the main focus. A good 85% of this RP will be personal, not military action.
Sven's percentage idea is a good way to abstract it, but again I'm not going to force anyone to go that far in-depth. If you want to update your profiles to represent it, great, go for it. But it won't be mandatory.

Guys, we're hitting that mountain/mole hill barrier again, so let's just do this. The baseline for armies will be semi-modern, i.e. basic bolt actions (either single shot or box magazine) and basic artillery. That is our 25%. If people wish to supplement their armies with less advanced forces, that is their own prerogative. As much as I hate to do this, this is my final say in the matter as GM.