Sure it's harder and annoing and Core masterys are a big waste of time and self gimping if there are not more points to spent then we can put into the mastery trees. You are 100% right with this.
From my point of understanding Core skills are just there to compliment your builds at a certain point and intentionaly lack power and give stuff like better mobility, tankyness or some minor buffs you don't care about at all.
I WANT my godly blessings to be better and more intresting then good old human "I hit things often and hard and see what happens".
I WISH core skills had more synergys to interact with the skills we use so we can start to make some builder/spender playstyle happen but right now you can sustain spamming exhaust skills that deal 40k+ dps.
Maybe it would be neat to get a Core Mastery point every level up to spend it freely but even then I would only buff movement and barrier because the auto attacks are realy bad no matter what.