I was expecting the config for 'slowdownFactorEmpty' to affect all minecarts not occupied by an entity, including hopper minecarts, but it seems the scope of the config is entirely inconsistent.

The slowdown affects TnT, Furnace, and empty minecarts, but the 'slowdownFactorOccupied' option affects hopper minecarts, chest minecarts, and occupied minecarts.

The deceleration factor being applied to both occupied minecarts and hopper minecarts means a decently fast acceleration will render all farms that use hopper minecarts useless, since they will always go far too fast.

We can set a custom speed for set blocks that the rails are upon as an alternative, but is unintuitive for players on the server that didnt see how to slow them down.

Also, perhaps a maxSpeed for just unoccupied minecarts, or even per-minecart, would be fantastic, where once left the minecarts would decelerate down to the set maxSpeed.

Possible additional idea:
Config to exponentially decelerate down to a set minimum speed if many normal rails are placed consecutively?
It's just a bit weird to have a path this long with only one powered rail still infinitely gain acceleration.