I find that Ducati clutch systems can be a pain to bleed as you can't get the pressure as you would in a brake system due to the slave moving freely and not up against a dead stop.
I found that when fitting a new full clutch system i.e. slave/master/line etc. it was much easier to fill from the slave end upwards using a large syringe as it naturally pushes the bubbles upwards whilst filling - not sure how much help that is in a 'full' system though?
However if your clutch was working OK and then, suddenly doesn't get the plate separation that it sounds like something else is amiss.
Would advise you check that the clutch hub hasn't moved outwards and having lateral play, usually due to the star washer eating into it or even the hub nut coming undone, I've had both happen on my 916.
When the hub nut came loose it actually ended up 'ejecting' the hub, plates and cush rubbers through the fairing, leaving me stranded and picking bits off the road. Happened on the first ride out after a dealer had fitted a new clutch, they told me "the 'O' ring had let go"
(I have to say I find that hard to believe when torque setting is 180nm or so but after they'd repaired it (and fitted a new side fairing and clutch cover) I finally made the decision to stop going to dealers/bike shops for repair or service.)
I also had the hub 'eaten' away by the star washer meaning it can move a couple of mm away from the basket resulting in insufficient clutch action and the pressure plate rubbing on the cover - apparently this is quite common as the cush drives allows this movement where the star washer rubs lightly on the face of the hub.
I've read recommendations of applying a light film of grease under the washer to help prevent wear? another solution is to replace the OEM hub with a billet unit that has no cush rubbers and so eliminates the problem whilst saving some weight.