I think if you compare this to ME2TW for the mechanics you might be close Its not necessarily the amount of units its the training or upgrades your units have vs your opponents. Assumeing DoF has unit upgrade trees.
I have taken 1200 troops against 2000 and won several times, It takes strategy and a awareness both of which you hope your opponents lacks.
Personally I think stealth should be limit to natural surrounding like trees rocks, etc. in ME2TW you gain a certain amount of stealth by keeping you units in wooded areas...