One question - have you Captcha add-on installed? :-) I suppose having it you won't need all these things.
Here on miniBB, I've just installed Captcha to prevent automatic registrations and guest postings, and created Spam & Flood thread
. For some time there was few manual spam, until spammers discovered it is bad to leave message here, because anybody can discover their "business" page in search crawler, noticing sometimes it was promoted via spamming the other forums. It is very bad sign for a business :-) I already received couple of whining requests to remove spam messages from this thread, but what I did just showed the middle finder. No way.
I also banned few Chinese networks.
For some months, there is NO SPAM, at all.
As about new Premoderation - thanks for the suggestion #1 (straight remove from premoderation queue), I will keep them in my list and probably sometimes will implement them... but since this add-on is kind of unprofitable and low in sales, I still can't allow much time in additional developing.
Deleting a member from the messages list is a very difficult process and I doubt I will implement it at all. Maybe it would be just possible to create kind of link which opens the admin panel's page where you delete the user, with automatically substituted ID.