I wouldn't assume the DW abilities are going to come back.
There have been event pokes with different abilities and moves before and it's not like they've been made available in future games. The DW stuff might not be any different.
Besides, GF likes to encourage backwards compatibility - I'd be unsurprised if the DW in BW/2 remained the sole way to get those abilities.
That said, the new gen of pokes would be at a disadvantage if everything preceding them had a wider range of abilities. So there might be an equivalent. Or they might just balance it out with, yknow, power creep. Which would be ironic. And wholly precedented.