Heroes 5.5 WarGame Edition - Tactical Edition.

In the new layouts, there is no need to discard buildings, as there is no shortage of space.

In your 5x5 layout, there are 3 free cells, compared to the 5x6 layout with 6 free cells in the standard version. If all buildings are returned as separate structures, only 1 free cell will remain, which will make balancing and player perception of the building layout more difficult. (I didn't quite like the 5x4 layout with 1 free cell.)

It is possible to return building types like farms with a similar bonus as when upgrading (+200%), but not as a one-time bonus, but weekly (to the increase). For example, militia farms +16 militia per week. Place them as an additional upgrade after the grade (in the same cell).

I don't see a significant loss from buildings with increases, unlike the other "racial" buildings, but if it's done as an additional upgrade, it's worth considering. But then it turns out: base income 100% + increase 100% - upgrade income +200% - upgrade increase - 200%. That is, for militia, the base is 10 - fort 10 - stronghold 10 - castle 10 + 20 upgrade increase (instead of 40 max increase 60). This will not fit into your concept of a 10-40 increase, as you wanted. I don't see the point in reducing the base to 7, since the one-time income of militia will be: 7 base + 7 upgrade = 14, which is significantly less than 10+10=20 (in my opinion, a base of 10 is better). I think buildings with increases are not worth it and only interfere with balancing!