I think that you are right on the neovascularization / contraindication. Perhaps the ACP / vascularization is required in this instance to initially provide tendon cell proliferation for the healing which did not occur after the injury.

The eccentrics (and perhaps reduced vascularization) can be considered later when the tendon has progressed to better handle the load.

One thing is clear - - I'm way out of my league on this discussion!!