Hesitation about writing a paper
Given that a correct and satisfactory proof exists in the literature, you would not be providing "research results" per se, so a full research article probably is not worth writing at this stage, unless you can devise a more elegant or straightforward or otherwise "improved" proof.

If you are unable to provide that, it would certainly be appropriate to comment on the difficulty of correctly proving the theorem, and do a "comparative" study in the form of a letter to indicate the challenges and make them known to a wider audience. 

But, as you said, it's certainly a matter worth talking about—it really is a question about the appropriate "form" of writing your results up.