Many people use something like denyhosts or fail2ban to help with brute force attacks. PF has built-in support for building rules with options which will throw potential attackers into a 'penalty box' based on certain factors like connection rate.
Since nftables is supposed to be backwards compatible, I'd guess it can do this too. I wonder what it'll look like for that. A lot of the other syntax looks nicer, i suspect that this will be better too.
That one I haven't seen before, I wonder if the new nftables might be able to implement any of that. Based on the state machine specs probably not, since I don't think there's any storage or any way for it to generate new rules on itself based on what I've read.