The changes in appearence is from the developers. Halo 1,,2 and 3 weremade by bungie while halo wars was made by ensemble studios. When creating the models for the elites the company tried to copy the original elite look as closely as possible but could not do it perfectly. Since copying the models from halo 1,2, and 3 is restricted from legal issues and the fact that halo wars uses a different game engine means that ensemble studios had to make a new model. This is not uncommon in spin-offs. When a game franchise (such as the halo series) puts the development of game based on their franchise into another companies' hands they tend to let that company do their own work while they supervise. Even then the franchise usally distants itself from that spin-off in case of bad press. The changes