I don't think anybody knows what will happen under EASA because it is a more or less entirely political process.
The NPPL is not an ICAO compliant license and this is why it is valid only in the UK.
EASA looks likely to introduce a pan-european version and it is reasonable to assume that NPPL holders would be grandfathered into that, at the appropriate time.
Whether an NPPL is worth doing is a separate argument. IMHO it is a waste of time - unless you cannot get the CAA Class 2 medical. In terms of flying skills you need the same amount of training to reach a certain level, no matter what license you get, and if you go for the JAA PPL then you have a worldwide-usable piece of paper.