It'l normalize over time, wot and other similar metrics should be robust to small changes like if someone follows a bot by accident or whatever.
Of bots are useful, they will have good trust (being followed but not following others). Dave is a useful bot, there are a few time chain bots that are useful.
if a bot is bad it will get buried from mutes.
in the middle has a similar score to newcomers, which should eventually classify as show or don't show in feed after a number of actions happen.
Now, malicious actors? Purposely inserting them in communities to sow division - yeah WOT can't protect against that. Only the strength of the community can hope to guard against that.