Cross server SWB is problematic due to player matching.

Matching players via level? there can be 15k difference between a f2p and a p2w player at the same level. Power matching? you can change your lineup once you enter the battlefield (i think, hadnt had SWB in a while... server 407 needs a merge =P).

That being said. In my opinion loosing in SWB its still better than having no SWB. Thus cross server SWB should only be triggered if your server has not enough people lo open the battlefield and should try to match the servers closest to your number. Depending on how the game was coded, implementing this can be a huge pain in the a**, taking a long time to actually be introduced.

Enjoy SWB while it lasts, servers tend to depopulate as time goes by.