I've been holding back my vote for a while now, but I have finally decided on a No.
I bought a 1080 beginning of January, an upgrade from crossfire 280x's. I was absolutely blown away by the 1080,the performance increase was huge! The Ti would be another improvement, but nowhere near as big. I'm getting a solid 100fps+ in BF1 at 1440p ultra, I don't need anything more than that. I'd rather put my money into a custom water loop and clock my 1080 even higher, and eventually look into a hex/octo core cpu.