Third party DNS servers are helpful in one sense - you can share your state with other users.
Turning off EDNS with your own recursor won't really make much difference. Limiting the maximum cache length will help, but will also eliminate much of the benefit of having a local recursor.
The other issue with running your own recursor is nasty networks will transparently proxy DNS and you can end up using a cache you don't even know exists.
DNSCurve, DNSCrypt, and DNS-over-HTTPS solve one set of problems while introducing different ones.
Turning off EDNS with your own recursor won't really make much difference. Limiting the maximum cache length will help, but will also eliminate much of the benefit of having a local recursor.
The other issue with running your own recursor is nasty networks will transparently proxy DNS and you can end up using a cache you don't even know exists.
DNSCurve, DNSCrypt, and DNS-over-HTTPS solve one set of problems while introducing different ones.