But then how exactly do you think they will do it? pehaps a special type of template, or perhaps templates will become more...mutable in 4e?
See, apparently any creature can become plaguetouched. Furthermore, this mutates, and grants them weird powers...possible in addition to what they could do before.
So a plaguetouched dragon might have a plagued breathweapon, two extra wings, four eyes, in addition to everything it could do before.