You might have seen the "join Illuminati" spam comments coming from the 197.21x.xxx.xxx IPs (Nigerian). I'd like to suggest blocking this IP range. Blocked IPs will be able to view the wiki but not comment/edit.
FYI - I got in touch with Fandom support and they turned on the AbuseFilter extension (description). It can block comments that match a text pattern and autoblock the offending IPs. I think this will be a good addition (or maybe a better alternative) to the existing IP block.
I'll set up a filter for those comments some time later this week.