I love the idea of IK having a pet build option. I think you could achieve the same goal without quite so much development effort though, if you just give the CotA skill an appropriate multiplier. My personal opinion is that IKBB’s CotA moves to orange text and becomes appropriately large, 600% or so.
I do like the idea that Ancients share your strengths, though. I think we might be past the point where radical set changes are on the table. I think the fundamentals of IK are solid, so I would leave it alone except for buffing the 6-piece.