2 ideas so far (no stabbing in either of them... sorry G)
#1
Perhaps it's not the most thought out plan but I'll throw it out there:
peer review ! Might sound like corporate lingo but hear me out !
Add a report "Troll" button. And after a certain number of reports by different users, let's say 21 ( blackjack!), than 5 random users that do not have the alleged troll in their (un)trust/ignore list, did not quote any of his posts, did not post in the threads with reported posts, have over 50 days logon time and similar rank (+/- 1) will receive an automated PM with 2-3 random posts that were reported and to reply with TROLL or NOT. If 4 of them say TROLL... then he receives a 5 day temp ban. Next time X2 (10 days), next X2 again (20 days) and so on and so forth...
Upsides:
- the community will decide
- it will incentivize not to reply to the troll so you have a change to "assist" with a temp ban
- the responsibility does not fall on the shoulders of only 1 person (be it mod, admin, satoshi etc)
Downside:
- most likely a bit too much db info should be stored.
Similar to a few games community version anti-cheat systems.
#2
Probably been mentioned before but adding another trust list related to post message, logic, thought process etc Another trust that does not reflect on trading risk... let's call it a bullshit-meter
You have the same options to add users to the list of people you agree with, that sound coherent, that come with relatable examples... in other words people you think have a lot of value in their posts or ... bullshitting trolls.
And you could see messages like "most of the posters you trust consider this user to be a troll"
The only catch is: you can have different "troll ranks" for each main board. There might be a guy who is very technical, helps out other users, contributes a lot but... he's a nazi. (not pointing any fingers here, it's just an example). In the Bitcoin main board (Bitcoin Discussions, Technical Discussions etc) can have a status of "people trust his judgement" and in the politics and society board ... meh. This will only appear for others, not something that the alleged troll will see him/herself on his/her profile.
This also has it's own ups and downs but I do believe there is a need for this as there are lots of trust feedbacks given for trolling and not all trolls are thieves. Orcs yes, but not trolls

Food for thought...