I will pass along your thoughts to the owner. The Mod Corner has always been an extra benefit provided to those whom have current access to support.
Here is my personal opinion since I remember the old site and I think you do too.
Even from the early photopostdev.com days when everyone could view versus now I do not beleive personally opening the area would change anything there. That site was closed down due to low participation. The problem has always been the following. There really are no active users whom have much knowledge in coding and releasing mods or they choose not to share. The users that would actively developing mods for our software would have current members access to code.
What is really needed for the MOD CORNER to be successful is not opening it up to anybody. It is for users like yourself and others to write mods that people might want and release them.
I do not have much time myself to do mods as the job takes most of my time but I beleieve the ones I have released are widely used. If some other people released mods then I beleive thats how we can truly get the site going. Plenty of people view that section the real issue has never changed and this is what is needed to make the section successful.