Question: Is there a good decicated place (or website) where people can proofread texts in Esperanto?

In this place, people could correct errors and show how they would have written. Proofreading is good for improving writing proficiency, so this would be a valuable ressource for Esperanto-learners.

Answer: 
[Lang-8](http://lang-8.com/) is not Esperanto-specific, but it exists pretty much for that exact purpose. You can tag your entries as "Esperanto" and people will find them.
Some local esperanto clubs do proofreading. Especially for short texts, stories, video publications the local clubs can help.