I must say although Id be happy to see Dorian go on for a little longer, I'm in the 'if its over, its over' camp on bringing back series - even ones I really like I can accept that they can (and should) come to an end and feel that, once that decision is made, that should be it.
Graceless is indeed a case in point. I'll get it (and no doubt enjoy it too), but I do think that it ended on a good note and it would have been better to leave it there - and create something new to take its place.
Well, Simon also wanted to give Graceless a definitive ending. And yet he did come up with a sequel...
As I noted above - Simon is one person. Scott and Alex BOTH wanted to end Dorian. They'd both need to agree to go back on it and since they both seem sure 5 - and a bunch of specials - is as much as they want to do. Surely with two of them saying "I'm done" it's twice as unlikely to come back You could well be right though if we wait long enough. Strange things DO happen. I never though Paul Magrs would work with BF again and let Iris come back.
I would NOT want Dorian recast (more than the older one we've had in-Universe) but I doubt BF would ever be so silly. I'd also not care for anyone but Scott to produce it either and I'm sure Alex wouldn't be that keen on changing the team anyway.
Either way - we've still got 2 series and Christmas to come. Plenty to chew on.