Weapons for mages.

The game has begun to pay much more attention to the diversity of elements used in skills. The infusion system directly requires this.
However, mage weapons have suffixes:
+ to Lightning skills.
+ to Fire skills.
+ to Cold skills.
and finally - + to all Spell Skills.

Each of these stats (especially high-level +4, 5, and 6) is incredibly rare. And costly. (hey! i find +6 staff for fire... what you mean - "no one needed it?!)
Melee classes, archers, spear, etc., are content with only one stat: + to Martial Art skills (or + to Melee skills)

So why mages need + to light/cold/fire skill if we use all elements now?
Can we combine these parameters just to only one - +% to All Spell Skills?