Vyaiskaya:Most of the people might converse in English here, however I would argue usually the Japanese title is the one used when referring to a Japanese series. (Katakana Eigo is typically de-katakana-fied.)
While, in my experience, that’s true for programmes that don’t have an official English-subtitled video release or only got one years later (even though they have an English title in the network’s sales catalogue), it’s not for ones that get worldwide releases on streaming services much quicker, as many do nowadays.
When does anyone writing or speaking in English call Alice in Borderlands “Imawa no Kuni no Alice”? The two editorials on MDL about it don’t.
I also wonder whether MDL users referring to J-dramas by romanised titles has anything to do with the dramas having romanised titles as their main ones on MDL and that making them the best-known titles on this site. However, even then, there are the exceptions I mentioned, which will continue to be a greater share of J-dramas now that speedy worldwide releases are much more common than they were a few years ago.