I don't have too much to say here, but I feel the True Damage aspect is very vague and needs to be clarified, both aesthetically and in the tooltip.
First, I heavily implore you guys to add a burning animation to any and all targets affected by Warrior's Wrath, similar to how Spirit of the Lizard Elder did, to visualize it's duration and effectiveness (especially due to the fact that the other jungle items all have visuals tied to them, doesn't make much sense to have your True Damage DoT be near if not totally invisible and feel underwhelming compared to other options).
Secondly, IT NEEDS A BASE DAMAGE so that it doesn't benefit solely single target damage. (perhaps lower the percentage of phys damage converted along with this) It also enhances the feel of reliable and certain damage, as well as allowing less powerful AoE tools to benefit from it. (rek'sai Q as an example.) It currently feels really ambiguous and unlike a solid item.
If I were to change this drastically, I would implement the Spirit of the Lizard Elder version of this effect complete with, scaling via levels (because honestly, you guys did a pretty good job with that version) with base damage buffed to ~20, but I know that probably won't happen.
As for the upgraded build path, good job. I've been wanting for this change for a little while now.