Let me just say that I once loved the DS9 siege mission (except for the end). I've played with big and small groups and it was always a fun challenge, that is until recently.
I don't know if something has changed, but I seem to recall that if you were on the upper level and the Cardies were on the lower level, you could use the balcony for cover. Now, they seem to have acquired amazing leaping powers, enabling scores of them to meet you on the upper promenade, negating the reason for two levels. Also while on the ground floor, they can leap away to the top to avoid getting shot. It's like playing with a room full of mobs using cheat codes.
I quit out of frustration for the first time today, not wanting to bother fighting wave after wave of holo-cardies from the upper and lower levels all at once. Terrain and cover should be useful; here, it is not.
Oh, and the time before, the force fields were bugged, locked at 4/8 disabled even though they were all down.
The Breen were doing the Superman leap to me yesterday in those weekly missions from last year. It's interesting that a guy clad in who knows how much armor can leap 4 stories and use that as cover from you, but you can't be on an upperdeck to use as cover without your enemies jumping up to meet you.
It's a recent bug I think. DS9 bugged out for me last week at 6/8, put in a ticket and was advised to drop the mission and wait 15 minutes to restart I think that CS person might have been skimming through a pile of tickets.