Situation now on relay admin side if everyone turn on WOT they will able to stop random npubs of spamming
But that will CLOSE all new genuine user npubs from posting in such relays. Right ? Hence relays need keep open withOUT WoT but with POW 5 or POW 10 only. This is allow fresh npub post once in while throttling any millisec bots.
Client side Reply filter is NOT much of an issue. whitelisting npubs for test in relay also work fine for test npubs.
 

 Why not have both? If you have a low score then you do pow? Make the client check the relay response and manage it accordingly? 

 just tested POW + WOT both enabled - it stopped me post from non-POW client - so POW will additional STEP that can be ENABLED optionally.
but poster need  use compatible client in that case. 

 I guess it would require changes on both the server and client side to work how I imagine it. I’d expect to attempt to post a note and then it just goes through because my score is good, or it would return stating the client must meet POW requirements because my score is too low.