I know I'm stepping into the dark side with this inquiry as in the end I know it's up to me, how ever I'm just looking for a little more clarity on this decision I think?

I currently have a D5000, Sig. 120-400 and Nikkor 24-70which are the 2 main lenses I use for wild life, family shots and walk around.

Putting aside the $ factor, I am looking at the new Sig 150-600S first and then getting the D7200 and the D750, but not sure regarding the Bodies as to which way to regarding the Body, (All subject to change without notice of course).

Any helpful thoughts appreciated.