If I had to do what I say (Which is of course the hardest way to do it I'd more than likely make RotR a complete overhaul.

Change the Preference to Cold 1 or None (Depending on the points).

Remove Wingless, Remove Mammoths, Remove Spire Horn Warriors (Replaced with Raptors), Make Raven Guard Sacred. New unit Gryphon. Move one Air to Random on the Harab Elder and give him Holy 3. Starting Spell = Blight.

That would play much differently. With the removal of Cold preference but keeping the units Cold Resistance, you could take Cold if you wish; but you lose the 'free points' and makes you play quite a bit differently.

Those are just some things I was thinking for my own modifications; but hardly a general consensus.