At the same time, the variety of settings is also a downside, as it requires agreement before the game and extra actions before each generation.
Another downside for me was the frequent desyncs, but memory suggests that most, if not all, occurred in games with the same player.
Until recently, a downside was the author's indifference to the project, but it seems to have improved now; here is http://www.heroesportal.net/tavern/?id=254759&pagenum=6 a link to the latest revision with some bug fixes. Apparently, it should have been re-uploaded somewhere on HeroesWorld.