The problem with making Magus a more distinct enchantment is...
that we have just a huge Variety of possible AP junglers to make it distinct with.
Our current "Meta" Ap junglers would be 
. Some off "meta" AP junglers would be within the ranges of 
.
Many people would agree that the main problem is that they run out of mana really fast, whenever they are without blue buff, which greatly reduces their clear times and increases the punishment token in jungle, resulting in fewer ganks and so on. So on that problem, people agree that Magus having some sort of Mana Regen/Vamp would help.
I'd argue that this would make mages in jungle way broken. Mage junglers, unlike fighters and tanks, are burst, relying on being assassins. Their mana restrictions in the jungle make up for their gank/kill pressure they can put on lanes. Adding in a way for them to stay in gankable condition while farming effectively might lead to Diana and Elise getting nerfed even more. Maybe Nidalee too.
TL;DR: By making their clear times, punishment and mana conditions easier to overcome mages would become considerably stronger. Even if this might be a good thing, junglers currently effective might be nerfed even more than they should be.
