It's not all about loads, though. Yields are what count. Particularly at the moment, full aircraft, particularly in the past, are not an indicator that a route will work. That said SN operated, and pulled, ORK-BRU in the past, so just because one airline canned a route does not mean it can't work.
I think there is opportunity at ORK, as you say routes like VIE, FRA, BER, ZRH could all have potential. I'm not sure how things will work out over the coming seasons, but I can see ORK becoming a split A319/A320 base. Probably 2 A319s and 2/3 A320s.
On the face of it going to a 4/5 aircraft base might seem risky, but the addition of the A319 and the ATR to the EI fleet changes things a little bit. The possible closure of the LGW crew base could change things too. Consider that an ORK based aircraft could operate ORK-LGW-NOC-LGW-ORK and take over some of the EIR rotations to MAN/BHX. This would allow the likes of EMA/LBA to be introduced on the ATR's. In that scenario adding an extra aircraft to the mainline fleet at ORK is reasonably low risk.