Well, that's what happens when you keep on using a character based on the Gen 1 protagonist in later gens.
However, you did see more significant design changes with other older characters who appeared in later sagas. Compare how Clair looked in OS to how she looked in BW, for example:
[IMG]
Or, Steven in AG vs Steven in XY:
[IMG][IMG]
Of course, unlike Clair, Steven at least still looks like the same person, but that's more of an issue of Clair's HGSS look being completely hideous and OOC than anything the anime can be blamed for. {XD}
However, you did see more significant design changes with other older characters who appeared in later sagas. Compare how Clair looked in OS to how she looked in BW, for example:
[IMG]
Or, Steven in AG vs Steven in XY:
[IMG][IMG]
Of course, unlike Clair, Steven at least still looks like the same person, but that's more of an issue of Clair's HGSS look being completely hideous and OOC than anything the anime can be blamed for. {XD}