Please do remove all limitations. There are many cases where it is essential to be able to modify a post even years after the fact - for example, I maintain the Ivan sticky at RC Groups and am still editing the first few posts over 10 years after the thread was first begun. This allows people new to the thread to see all the updated information right at the very beginning without having to read through hundreds or thousands of pages of discussion.

It is also very useful for posts in the marketplace if for example you want to modify your listing, for example, to lower the asking price.

I could go on, there are a multitude of reasons to edit an old post. Before the conversion there was no limitation even here at RCU, and there should be no limitation now.