That should be obvious by now. 😃
Due to the cost structure of attributes it is slightly more efficient to favour one attribute but in a longer game this is completely irrelevant and you can simply get them all.
I would go for a more hardcore approach like having one primary attribute and all secondaries cost more... but that's the stuff of mods and super unlikely to be in vanilla.
The only real issue is that there are very few actual "special enemies" by now. They all have hit points, are affected by all weapons equally, have very few special abilities.
(there are minor adjustments for armor which only ranged weapons and spears/clubs have means to deal with)
That is going to get fleshed out. It's part and parcel of the whole Tower Defense bit.