Depending on where you came from its not as bad as it sounds.
I came from an airline where the chosen few picked trips and sweet talked crewing, where rosters often, changed multiple times per day. where there were no protections and rules about what could and couldn't be done.
Even if you are junior in BA, the system is utterly 'fair' and transparent. (for a given value of 'fair'! some people may not think its fair but there are a set of rules and equations etc that govern the system and everyone is treated equally within those rules. No management pets or crewings 'mates' nicking all the good stuff)
Nothing changes. Once the roster is published its cast in stone. Again depending on where you come from that may or may not be a big change. But for me that is a huge lifestyle improvement - I had no Idea how much of a improvement that roster stability makes to your life - but its indescribable how much it improves everything - even on a psychological level, knowing that you are not one phone call away from having your life f**ked up again is great.
Yeah, you may work weekends -I'm on a smaller fleet so its not as bad as maybe the large fleets are for junior guys - but I've got blindlines this month with a few weekend days off. The days I 'worked' werent that bad either. a saturday with a 21:00 local report. Today with an early day trip but back for a late lunch.
Also The one roster I've had so far with all weekends worked, I had every single Tue-Thurs off and some mondays and fridays - so a couple of 4 day blocks off and about 15 odd days off in total.
Personally I think its a great system. Those that moan about it the most probably haven't experienced first hand some of the other systems that are around!