I don't know what the writers originally had in mind to finish the series but the ending as it was done now was clearly a rushed job because of early cancellation combined with the writer's strike at the time.
In the first few episodes of the series in season one I was annoyed several times by irrational/illogical behaviour by some of the characters needed to create the storyline. This returned at a highly elevated level in the last episode.
So Danny was building up promicin in his body. Gee... what to do.... Oh wait... Isabelle was also producing oodles of the stuff earlier in the series which they got out of her to fill a gazillion of tubes with which to inject people. And later we saw p-positive people donating promicin on a weekly basis to create new stock of the stuff. Oddly enough nobody even considers the possibility to do the same with Danny. Not even this supposedly rather clever scientist Burkhoff chappie.
And wait a minute... didn't they have someone who was able to take promicin abilities away from people and return them to being p-negative? Yeah we've seen it done several times. Okay so this Collier dude was missing at the moment but did anyone even suggest they should increase attempts to find him (surely there would be enough p-positive people with highly useful abilities to find him) and have him take this undesirable ability away again from Danny?
Nahhh..... doing any of these wouldn't have allowed for the killing off of Danny for a mildly dramatic effect totally not worth these stupid inconsistencies. I had hoped the Director's cut would at least have corrected these annoying inconsistencies but unfortunately not. Bad Director!