It seems like requiring the client to provide proof of work (e.g. Hashcash[1]) could be an easy way to help reduce the asymmetry. [1] https://en.wikipedia.org/

It seems like requiring the client to provide proof of work (e.g. Hashcash[1]) could be an easy way to help reduce the asymmetry. [1] https://en.wikipedia.org/wiki/Hashcash https://en.wikipedia.org/wiki/Hashcash