Spirit gems from bosses

Could we get a level appropriate spirit gem from every boss encounter? All I have to do is kill mobs for 5 minutes and I'll end up with 1-2 uncut skill gems, but I can go an hour or more without a spirit gem drop. They are far too rare for their importance to some builds. This will put off experimenting with builds for a lot of folk, or limit it to people like streamers or those lucky with currency drops.

Having a reliable (or at least high probability) spirit gem drop from bosses will facilitate greater build flexibility.