My common workflow when I see a blatant spam post by a 1 rep user is:
- flag as spam (when I'm a mod this auto-deletes)
- go to user profile
- As a mod, I destroy the user. As a regular user I spam flag the other spam posts linked from the profile
These are a bit more clicks than absolutely necessary. While it is not terribly important to optimize this, it would be nice if we could perform these steps with even less effort.
My main assumption is that a 1 rep user that has one of their posts flagged as spam until deletion is almost certainly a pure spammer. I might be wrong there, but I've never seen an example that violates this rule.
Having to go to the profile is an unnecessary step, but I always do that to determine if the user has created more spam posts. Destroying is also not necessary, but it is quicker if the user has multiple posts, and if I have to go to the profile anyway it's also only a few clicks away.
To make this quicker, I suggest that users that have never earned any reputation and that have all their posts deleted by spam flags should be auto-destroyed. Destroying accounts doesn't really slow down spammers much or at all, but it is somewhat tidier and many mods do it anyway, even for single post spammers. It would also serve as feedback that this user can't possibly have more spam posts, preventing other users from checking the user's profile without need.
When I spam flag a post from a 1 rep user as a mod, I'd like to get immediate feedback on how many other posts the user has, and maybe even a quick way to directly preview those posts and destroy the account.
This would of course not happen for posts from real, active users due to the 1 rep limitations. Excessive self-promotion and other borderline spam issues are usually not dealt with by account destruction. This restriction also severely reduces the potential for abuse of this feature.
As for leaving accounts alive to gather information about spam URLs and/or IPs, this is something that should happen behind the scenes anyway that that we mods should not have to think about. The community and mods provide enough information by spam flagging, it would just have to be collected and aggregated by SE internally (and maybe this already happens).