Why the new runeglaive will fail
Okay, I'm glad riot is trying to help AP junglers. I really aim. I love AP evelynn. That said, I don't think riot's efforts will work here.
The new Runeglaive is trying to help AP junglers by increasing the amount of damage to monsters. This is supposed to help AP junglers clear. Here's the problem, AP junglers are flawed because of their early clears. The beginning of the jungle on your first two clears or so, you are largely dependent on your AAs as a jungler. Your skills generally aren't enough.
So as stonewall points out you need a good base value on your spells if you want to clear as an AP jungler. So if you have good base damage on your spells, why are you wasting them in the jungle instead of using them to wreck enemy champs from level 1? If your spells aren't good enough to clear the jungle by themselves, you can't jungle. Now if you've got a skill that has good AP scaling, junglers can't really afford them because junglers are poor. So if you've got a champ that needs items to scale, you are forced to lane whether you want to or not.
At the end of the day, the new runeglaive doesn't help junglers like the old one didn't: they just don't need that effect to jungle by the time they get it. I mean runeglaive was nerfed because it was better on laners than it was on junglers... See PoE.