My work is always getting criticised and bashed and what not ( mostly constructive criticism ;) )
I've gotten so much criticism, I've become desensitized by it @_@
have seen work out there that's pretty decent, and I've seen work out there that ... isn't as strong (is that the politically correct terminology to use?)
but it makes me wonder how good does your art work need to be when producing something like a web comic?

There are absolutely no standards for being a webcomic artist.
 
There are also absolutely no standards for being a webcomic critic.
 
I'd say if you're happy with your artwork, and your fans are happy (and I mean REALLY happy, not just stroking your ego), then you're at a nice comfortable spot. But you should never stop honing your skills; that is a lifelong process.