I only just realised ToCS4 conversations were going on in two places, so I'm posting this to help other people find them. GOG subforum weirdness strikes again.

If you follow the 'Forum discussion' link from the catalogue page, you end up in this subforum, as players of 1-3 would expect.

If you go to ToCS4 in your account after buying it and click on More -> Forum, however, you end up here: https://www.gog.com/forum/the_legend_of_heroes_trails_of_cold_steel_iv