Well I don't think Apple will be as senseless as they have been with the iPad Pro. I think they will converge them, but continue to support classic Mac interaction models (keyboard + mouse).
With all the competition from Microsoft's Surface lineup we'll probably see the iPad shift even more towards the Mac side of interaction as well.
To your second point about performance: have we really seen what a high wattage ARM CPU can do?
Will be interesting to see if native iOS apps will be able to run for development or regular use. This is a good sign for the convergence of the Mac and "i" products.