Moderator on a Discourse forum since Spring 2017 here: I also longed for a single-click function on the user’s admin page to block their IPs (Last & Registration) for that member every single time I had to ban someone, but I kind of assumed no-one else minded having to go to burger > Admin > Logs > Screened IPs, paste it in, get that OK dialogue, have to click reload if the person displays 2 IPs…
It seemed too whiny and lazy and time-consuming to me to bother logging in here, and posting about it, basically requesting people put in hours of work to save me seconds of copy-paste, on at most a few occasions a month; also, I felt I should run searches and see if it had already been addressed and nixed, so never bothered. 
Urgent? Maybe not, though again it depends on how many of your staff are volunteer moderators, enthusiasts on the forum’s topic who are fitting in forum checks between work, family, other commitments, and how they may experience the added workload of the extra steps needed each time.
Especially because when you copy the IP straight off the member’s admin page it carries a space at the start (which copies elsewhere as a linebreak, not sure what that’s called), and that has to be manually deleted from the field before the IP can be blocked.
In the busyness of handling things after someone has had to be banned, maybe sending PMs and also trying to log everything relevant, it’s the most annoying thing in the universe in the 3 seconds it takes to be told
… but then, I backspace it and do the block, and forget about it until next time.
But it’s all worth it, because IP blocks are still an amazingly useful tool even now, and even with quite serious trolls.
While I have the list open, other things that would be nice on the same theme:
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single click to copy their IP and information on Location and Organization to my clipboard, so when I add this to Staff (where I am logging who was banned and why) I can paste it in one step. These have had proven value identifying grudge-bearing people who try to return.
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option to automatically add Banned as a title, so valued members don’t PM them/try to get into conversation, and feel upset to not get a reply.
That does have the same arguments against as IP address, this was what my computer showed me just now:
And the add-ons that did this are free, unlike a decent VPN.