LS is the only hope for a MAD service out of those airlines you mentioned. I think there's a strong possibility of that happening now that they've dropped BCN, so let's keep our fingers crossed.
ZB won't attempt MAD again I don't think. They've found their market in the solely leisure orientated destinations and do very well in getting high load factors on a daily basis to those places. The only exception being BCN which they've made their own and do very well on it. But MAD is very different to BCN. Tourist traffic to MAD isn't as high and it is far more business orientated. If ZB had smaller a/c then it might have worked better for them but they struggled to even half fill an A320.
And as for WW, well you can call me negative, but I don't think they'll launch another route out of MAN in the near future. They have absolutely no ambition and what small growth they do have seems to all be focused on BHX.
Anyway, back on topic. If ZB were to re-launch GIB they'd have to drop XRY as I really can't see both of them working together. Unless they can market the destination in its own right (as opposed to simply an alternative to GIB) and attract enough pax for both a GIB and XRY service to become viable. This would take several years to achieve, if possible at all. I think there will be a MAN-GIB service in the next couple of years but I don't think it'll be ZB. GB perhaps?