Yes, I agree. I have been getting like 1 conscript squad instead of a penal here and there, because i can get 7 man later, but I'm not gonna do that and have a diverse army if i need the global upgrade.
This basically only makes the upgrade useful if your con spamming, not if you just want like 1 or two con squads. Having t4 should unlock the upgrade without buying something in t3 if you want to encourage diverse armies instead of just making it a con spam upgrade.
That's the basis of all conscript upgrades... Only worth it if you want multiple squads of dead weight to invest heaps of resources into so they function only slightly below their counterparts instead of dramatically below.