Phage Usefulness and Entropy on Summoner's Rift.

So my group of League of Legends friends were having a discussion about old items and the old Frozen Mallet that built from Phage, and we were trying to figure out why Entropy was never added to Summoner's Rift with the changes to Phage/Frozen Mallet. As it stands, the only thing that can be built from Phage on the Rift is TriForce, and while that can be a very useful item, under certain circumstances, it does not fit every champion.

On the other hand, Phage, for its cost level has a very high usefulness. I, for example, build it early on almost all my junglers, and I do not replace it unless it is the end of the game and I am rolling in enough gold to buy Frozen Mallet outright. Its useful for jungle clear times, ganking/chasing, and handing out jungle buffs to the carries earlier in the game.

That being said, the fact that it only builds into one item that is not useful on hardly any of the junglers that I play, is frustrating, because its stat allocation is not worth the quality of the passive late game, as good as the passive is. However most, if not all the junglers I play would benefit greatly from building Entropy. Adding more useful stat allocation and true damage to the Phage passive would greatly benefit my gameplay.

So my question becomes, Should Entropy be added to the list of Summoner's Rift items? I cant imagine it being terribly overpowered, especially since even the non-Summoner's Rift Entropy was nerfed a while back, and though there have been comments of overlapping with Entropy/Elder Lizard, Spirit of the Elder Lizard, and all other current jungle items are being removed in Season 5.