Which is the problem.
In which circumstances is having experienced, veteran troops no better than having green recruits?
I don't mind having terrain specializations, I do mind not having any "core" promotions that are always useful, and the fact that all the other interesting specializations are tied into the specialization promotion tree.
I have no problem with shock becoming obsolete, it give you a tradeoff decision to make. Formation will become obsolete now, with no cavalry in the modern era, so its not like this issue is gone.
If the promotions are mod-able, we might be able to create something like:
Drill I/II/III: +20%/+20%/+25% combat strength in rough terrain, +5%/+5%/+10% combat strength in open terrain.
(Drill I-III = +65% combat in rough terrain, +20% combat in open terrain. Maybe even taking the secondary bonus off of the main bonus...? E.g., +15% against rough, +5% against open.)
Similar modifications for Shock, Accuracy, Barrage, (maybe) Bombardment, (maybe) Targeting, etc.
That way, if you put in 3 promotions, you're not "wasting" the new "generic" combat bonuses.
Looking at the list, it looks like we have the bonuses versus (1) armored, (2) ranged (defense), (3) mounted, and (4) (attacking) cities. We don't have one against gunpowder that I see, there's no point in having an attacking bonus against ranged units (getting them into melee range already is enough of a bonus), and it seems that a garrison unit only provides extra hit points or something (so no need for that promotion).