(I still consider stuff like Master level spells on gear a wasted boost slot...
WHAT!? I just found a lvl 20 Divine Sarong with +2 INT, double resist and +Winterblast.... Can you say WIN for a Hydrosophist? Being able to "memorize" three master level Hydro spells instead of 2... Now I can Hail Attack+Winterblast in a single turn and mass disease or mass heal the next turn if needed... Or vice-versa. Anyway... back to the topic.
There is a limited amount of 'boost slots' on gear.
While Winterblast might be nice for a spec with Hydro, it's a waste of a slot for any other spec, because the cost to use the skill is massively increased. You can try out how much casting fireballs from a wand costs if you have no point in Pyro.
So it's a case of good/bad luck to find a good boost combination. You just happen to have one char specced Hydro AND additionally, there is Int on the sarong. I consider this the exception.
As long as the ability level is taken to calculate the AP cost of a Master spell on gear, I consider them a wasted boost slot (which are limited in amount and 'quality'), no matter if you found the jackpot item or not. Most people aren't so lucky.
As I said, my own playthroughs were almost excusively done with crafted gear because of being less lucky.
(And as said, I was simply too lazy to rework the boost combinations in my own mod ;-)