Does anyone know how this 'JSS' is going to function?
My previous employers used preferential based system and it effectively allowed the top 10% of each rank to write there own roster while the other 90% got rosters that contained anything from 1 or 2 granted requests to absolute zero as it was based solely on seniority - if this is what BA are asking you to start using I would do everything you can to make sure it doesn't get implemented, even if they 'rotate' seniority it doesn't work ask the EK guys, the system is awful. BA has always been 'less money more lifestyle' it could turn into less money less lifestyle.
Not all preferential based systems operate to that extreme but has BA shown anyone examples of what the rosters would look like? If the bidding will be done entirely on seniority or if it would operate more like the leave system and be done using 'points/credits'? i.e I really want my daughters birthday off so use all my 100 points to bid for that day off, if no one senior to you uses the same amount of points/credits you get that day but with no more points to use you can't bid for anything else.
On a separate note how many long haul trips are being rostered under EASA? Normal 4-5 or have they squeezed in 5-6?