They specifically mention "sets that grant a bonus to melee damage", not "sets that give you more stamina, more weapon crit, more magicka or more spell crit.

So while it would make sense, I don't think they've gone that far yet.

• set that grant a bonus to melee damage

Correct me if I am wrong, but there are no sets granting you a "melee" damage bonus. There are sets buffing your light and heavy attack damage and there are sets granting you a Weapon damage - both have nothing to do with melee damage as melee is a range indicator, not a damage type.

ZoS, can you, please, be more specific in your set descriptions?

In fact I recall only 2 sets, involving "melee damage done by player" - Selene and Ashen grip - first one being the 2 fixed pieces Monster set and the other one is a crafted set, so they both have no need for "intelligent dropping"

^^What he said.

You can still get staves w/ weapon damage set effects, or bows with spell damage effects. You cannot, however, get a staff w/ a set bonus that buffs bow damage or reduces bow stamina use, for example.

It's a fairly small change, since there are very few sets in the game that buff a specific weapon set.