“additional enemies” ascension, adding roaches scales too differrntly compared to other monsters added this way.
Not quite, ‘add cockroach’ is a random encounter modifier, similar to chests, butterflies, etc. It is comparatively rare, 3 times less likely than Wooden Chest, for example. “Additional enemies” ascension currently always adds fixed monsters per terrain type.
Simplest fix would be to reduce respawn to 0..1, thus preventing “population explosion” outright. But that would be less interesting both flavor-wise and from gameplay perspective. I will try to rework them to make respawning less random while keeping the potential danger of drowning in roaches :)