If you want a forum without the freedom to advertise in your signature, you can literally choose from thousands of other forums. Go there, and see if it's better than Bitcointalk. If it is, you've found your new place to discuss online. If it isn't, you'll be back.

All we need here is enforcing the Signature Campaign Guidelines. I expect that would end all campaigns that pay useless tokens, some campaigns that pay in Bitcoin but at very low rates (I can think of 2 old online casinos) and it would finally end the biggest Bitcoin paying spam campaign Stake.