Re: Didn't someone previously propose
No, what's "clunky" is that the OP:
* thought that some post was interesting
* (presumably) reached into his/her knowledge of Japanese and pulled out "omoshiroi"
* decided to post it using Japanese script (mostly .... that space between the words tells a different story, though; I call cut and paste)
* added a superfluous attempt at "being polite" (as they imagined they should) (that "desu")
Other low-effort interpretations are possible, but they mainly revolve around the OP not really knowing Japanese.
If something is genuinely interesting and you want to express it in Japanese, it's just 面白い (+ Japanese exclamation mark, which I'm not set up for at the moment). Same as "itai", "mazui", "umai", and so on. Tacking on unnecessary "politeness" defeats the purpose and actually sounds sarcastic.