Looks like this setting was removed in v5?

Some of the signatures on our forum is becoming obnoxious. I'd love to limit to only text, no formatting.

Possible?

Only formatting available in your text editor configuration would be allowed. You can see available settings for signatures in ACP -> Members -> Groups -> edit group -> Signatures. I'm afraid, anything outside of what is available there will require a Feedback forum post to suggest it for possible inclusion in a future release.