Indeed, there's nothing like the Leveller (that I'm aware of) in the plugin world. Nothing does what the Leveller does, which is in fact a really useful trick. And it's so easy to use.
And since FXpansion hasn't chimed in (think they're focused on VST now) I'll do so for them Their 9-year-old EnvShaper, simple as it is, gives immediate results that you won't get from any other transient designer/compressor. Both of these (Leveller, EnvShaper) are irreplaceable outside of the RE world.
Leveller: https://www.reasonstudios.com/shop/rack ... g-leveler/
EnvShaper: https://www.reasonstudios.com/shop/rack ... envshaper/