Empire plays very similarly in 8th to the way it did in 7th. Everything that worked with Empire in 7th edition though, became much more effective in 8th. State troops hold the line better, warmachines kill things better, good magic protection is not as difficult to achieve. Captains on Pegasi got better with the single profile and armor boost. The only difference is that armies made up entirely of cavalry are no longer as easy to play with, even though, in my opinion, fast cavalry got a pretty big boost.