I have heard nothing to suggest that Wizz Air are considering using SEN and I cannot recall anyone even putting it up as a serious 'rumour'. It would be nice of course if it came about but I cannot see it happening unfortunately.
It really is quite hard to think of any established airline that might transfer existing services from LTN, STN or LCY to SEN so it really needs to be a newcomer to the LON market looking for cost-effective access. Adria is a case in point and the Maribor route does seem to be reasonably successful so far, so perhaps Stobart are looking to find someone similar. That's not likely to generate huge pax numbers though and easyJet surely has the most potential to achieve that aim and should be the immediate prime target for expanding its operations at SEN.