I kept Hagen safe, & my journal says to return to Marshel Cormack, but he doesn't want to know me.
I can only tell him.
1) I need to enter the Blacklake District.

2) I'm looking for Aldanon the Sage.

3) Farewell.

Any way to advance this quest, or is it time to put this game in the too buggy basket?

I looked at his conversation in the toolset, and it looks like you're missing a global variable. Try this:

Open the console with the console key (usually ` or ~)

Type:
debugmode 1
runscript ga_global_int("FaulkState", "4")
debugmode 0

Close the console. Then talk to Cormick again.

I get
Virtual Machine reports unsuccessful execution of script SetGlobalInt for object Vera Addams

Did you have your main PC selected when you typed in the console command?

Many of the console commands require the main PC (or NPC) be selected before the command will have any effect. :)

Yes I did, but I tried it again to make sure.
I've got a save from just before sailing to Neverwinter, I'll go back to that one & try again.

Edit:
Well I went back to the earlier save & did it all again & the quest has moved on normally this time.
It took 1/4 of the time I spent searching the net for a solution.
I found two other people with similar problems with the same quest, but they were from a couple of years ago & at a different stage.

It was my mistake. "SetGlobalInt" is a function, and you can't run functions directly. But there's a wrapper script for that function that does work (I tested it). The proper console command is this:

runscript ga_global_int("FaulkState", "4")

No semicolon at the end, and it requires quotes around the number.

I'm editing my earlier post to show the correct method.

Now my raid on Moire's warehouse was a success, but when I report back I to captain Brelaina I get:
you and I have no business I suggest you leave

Is this a notoriously buggy quest or just par for Neverwinter Nights 2?

I went back to an earlier save from before I entered the warehouse, but I arrived back at the same point.
This game is really starting to piss me off, are there any fan made fixpacks?

There is a known bug with Brelana's check to see if you resolved a quest violently or not. You might like this:
http://social.bioware.com/forum/1/topic/171/index/4541357/1

It doesn't list the city watch quests in the readme, & by the comments, introduces as many problems as it fixes.

I'll try one of the other campaigns, with is the least buggy?

I personally only experienced a few bugs in the very long OC, but they weren't the ones you mentioned, and they didn't break my game.

I didn't experience any debilitating bugs in the other ones either, but since you experienced some in the OC, I can't say if you'll experience some that I didn't in the other ones, too.

Well I uninstalled the game & redownloaded it & reinstalled it & started a new game (the OC)
And I am now in Blacklake without a single hitch.