The Magus jungle enhancement is completely outclassed by Morellonomicon
Each enchantment gives roughly the stats you’d get for the total cost of the enchanted item, so the jungle passive from Hunter’s Machete and the additional bonuses on the second tier items come effectively for free on the final items.
Above is a quote from the News post "Preseason 2015: A New Jungle".
Let's look at the Magus jungle enhancement
:
Cost: 2250 gold
Stats:
- 80 ability power
- 20% cooldown reduction
- Jungle passive and additional bonuses
Given the quote above, we should expect that an item that gives 80 ability power and 20% cooldown reduction should cost roughly 2250 gold.
Let's look at Morellonomicon
:
Cost: 2100 gold
Stats:
- 80 ability power
- 20% cooldown reduction
- 100% base mana regen
- Grievous Wounds passive
So I can get more stats for less gold with Morellonomicon. If I'm an AP jungler, there is absolutely no reason to ever enchant my jungle item. I am better off selling it later in the game and buying a Morellonomicon.