I haven't heard of anything to that effect, no.
We talked about it in this very thread the other day, but, yeah XP values are really weird now. Until a quest turns green it is going to give fairly similar XP to a quest in a higher level zone. Green/gray stuff is going to give shit XP though, like huge shit. This is for pre Warlords stuff though, WoD questing has higher jumps between zones (though not as high as previous expansions have had).
I want Timewalking Challenge Mode sort of stuff... gimme Vanilla/BC/WotLK Challenge Mode seasons. With revamped HD versions of old school gear sets and weapons as the rewards... yum.
I think stuff like this would be cool but it would be soooo far away. If there is a next step to timewalking dungeons it would be just getting more of them into the game. Heck they still have yet to come up with a compelling reward system for them. Old items scaling to a higher ilvl is neat but unless they increased the ilvl each patch those dungeons suddenly lose their appeal outside of a novelty factor. Hate to beat old drums but something something Justice/Valor points.
I'm sure character models took a lot of time/resources, just like rebuilding Azeroth did in Cata.
Don't forget garrisons. Garrisons aren't updating old models but if we're talking about taking the art team away from new stuff like mounts and dungeons/raids/zones that is certainly a culprit you should be looking at. Still stand by my previous opinion of T2 garrison art being a fat waste of resources that could have gone somewhere else.