MMH5.5 - Heroes of Might and Magic 5.5

I agree, but that way we cannot cover very strong perks with a chain of weaker/different ones, and we have to balance all the trees from scratch.

I understand, so this is not a desired measure, but a necessary one for balancing strong abilities. An alternative could be to strengthen weak abilities, although this is not possible for all abilities.
For example, in my mod, the ability "reduce magic damage by 15%" is considered a weak ability and cannot be naturally strengthened, but the next ability in the same branch is "+15% to health," which is very strong and allows this branch to compete with both Vitality + Power of Stone and 30% Evasion + Stand Your Ground.
Although, from the point of view of reducing variability, it still involves a sacrifice, but in this implementation, at least there is no concept of a "mandatory ability."