Would conducting legislative business via IRC (or text-only Slack/Discord) be a substantive improvement?

(or would legislators wind up texting A/S/L and deploying filibuster bots?)

Everything would be the same except it's not recorded. A transcript can provide transparency but would be much harder to sensationalize.

I've never voted, never will. Mainly because politicians don't really debate: that being, to convince an opposition to change their minds. I know sometimes politicians have gone against their party's wishes, but I can't see those being as a result of a well constructed idea from the opposition.

From what I can tell, there's plenty of that kind of debating done in German politics. Especially also because coalition governments are the norm.

Would you vote there?

This may have some truth in national politics, but state and certainly local politics have much more substantive discussions.