Permafrost,
It's early days for EASA FTLs in Longhaul but I think even under Bidline swapping is becoming more difficult. Unless you are swapping two trips which cover the same days you're now quite likely to fall foul of the rules concerning post rotation rest and/or pre duty acclimatisation rules. Also legit combinations for Longhaul back to backs at base are much more limited. I can say with some degree of certainty
that there are swaps in Longhaul that would have been legal in January but are now being refused due FTLs..
In short it looks like under either Bidline or JSS whilst you might be able to swap to get to a preferred destination, it's going to be difficult to swap to get preferred days off.