Halfway between Vita and Wii U in power sounds about right.

If they do make another dedicated handheld however, I expect it to suffer the same fate as the Vita. That market is disappearing.

with the new3DS right arround the corner, it seems like we'll have to wait an extra 1.5-2 years before a successor is announced, so 2016/early 2017 realease.

I'm betting on a slightly faster Vita (x1.5 / 2), with a 720p screen.
There's no reason for a 480p screen, it might even cost them more to put one since it's pretty obsolete nowadays.

The state of the handheld market is just one of many reasons the Vita failed to catch on. As long as it has Pokemon and Mario, as long as its price is right, a Nintendo handheld can only do so poorly.

Nintendo can't afford to ask for over $200 again, which is why I don't see their next handheld being a major power leap over the Vita.

So the 'New 3DS' is not classed as a successor even though it has it's own exclusive software due to upgraded hardware? This is like the Genesis/Megadrive days all over again.

Oh I agree the Vita has other reasons for failing; its lack of killer app software, watered-down-PS3 approach to games, and overpriced proprietary memory cards for a start.

But even 3DS is far behind DS in sales due to increased competition; mobile and tablet gaming is encroaching on the handheld gaming market from all sides, and I can only see it getting worse as mobile devices become more powerful.

More like the DSi.

What exclusive software did the DSi have? The digital stuff?

It could get worse, or it could get better. I don't think power will be the deciding factor for mobile devices. If Samsung or Apple starts putting physical buttons on their phones, that will be significant. Until then, Nintendo has a niche to fill provided their games are popular and their asking price is not too high.

I think it will be the HDS and it will be a massive upgrade in power over the Vita. I personally don't think Nintendo will go with the whole fusion idea.

DSiWare, yes.

There were 5 retail games that were DSi only as well, but that's hardly enough to be worth mentioning. Then again, we may only get 5 games exclusive to New 3DS too...