You can be highly worried about next gen dev-costs while still appreciating great graphics and a fantastic art style (in the case of Rayman Legends.) They're not mutually exclusive, and especially in the case of Rayman, the budget is probably half a shoestring with the engine already done.
In addition, the dev-cost argument, however much weight you personally assign it, still holds true for Wii U in comparison to the next Sony and Microsoft systems. Besides that, even with those systems a year off Wii U dev-costs (or rather, port costs) are negligible for most HD devs at this point.