Agreed. Sissoko would make a massive difference to us, especially if we aren't looking at bringing in a true replacement for Ba during this window.
As much fun as it is having all these signings come in at once, the only one I think will make an immediate difference is Mapou. Granted, Gouffran is an upgrade on Ameobi, but personally i'm not expecting too much. Haïdara (when he signs) is most likely back up for Santon so I can't see him being thrown in to the first team straight away.
That's not to say i'm not as pleased as most on here, far from it. I just that we need that little bit extra bit of raw quality to reinforce our chances of staying up.