Cant do it like that. It will be to unbalanced.
How will the game handle it when several paladins are in the same village. If I go 60% 0% 0% with an paladin, 0% 60% 0% with another and 0% 0% 60% with the last one, how will the game handle that?
How will it work with other boost, mounted archer already having an 40% booster item, will I be able to have 40% from item, 60% from paladin and 8% from tribe? Alongside an double 10% attackflag?
Innogames already does a lot of this, just creating boosts without thinking it though. There will always be players calculating everything, me included, and will be able to find things that is more or less broken. Right now tw is already very unbalanced and innogames really screwed up the meta, this will make things even more unbalanced, therefore I strongly vote no.