Guys? guys? GUYS!
1) Affinity shouldn't be so tied with tech > let me explore the web. As been said already, it's linear, simply beeline for needed affinity > profit. Not good.
2) Unit upgrades shouldn't be so tied with affinity = > again, let me explore the web. Getting OP units just by beelining affinity is NOT good. Maybe in addition to affinity level, there should be also a tech requirement for say, upgrade unit to stage 3, or even better maybe there should be stages within stages (yo dawg). What I mean is, umm, here's a simplified example:
From reaching needed affinity level, we got stage 2 'basic' infantry with 10 str, by researching tech A we can equip said unit with new weapons/equpment/whatever and it's now a stage 2 'veteran' infantry with 13str (with ability X). By researching tech B we can either further upgrade the now stage 2 'veteran' to 'elite' 17str infantry (with abilities XY) OR we never even got tech A, and went (reasons) straight for tech B, upgrading stage 2 infantry to slightly different 14str 'veteran' (with ability Y).
>
Now we reach needed affinity for stage 3 'basic' infantry with 14str. Now we CAN equip it with same tech A or B or both, netting us a more powerful stage 3 'elite' 21str infantry OR we can research techs C and/or D which gives us more powerful upgrades for stage 3 infantry, that stage 2 infantry could not handle (can't equip).
Oh, and of course all the tech upgrades and stage upgrades should cost money, because weaponry and war should cost money.
What do you think, eh? Eh? My IMO's on the matter, anyhow...