Well, both the UT are already used, but yet, putting it as a bonus doesnāt seem too strong, and it would be less changes to do, other than be easier to understand.
Maybe cavaliers too, but again, viets simply are strong vs archers civs.
This could be a weaker version, but in my opinion, 40% in feudal is balanced.
The free armor is useful as well, but te faster TT is more stronger in my opinion.
Well, with the 40% faster TT for foot archers, their archers rush could become really good.
You could put more vills on wood/gold thanks to the more food saved and have your archers sooner.
It could work well with the free armor too, but it would be weaker.