Making Handler a transformer

How do you guys feel about instead of having

newtype Handler a = Handler { runHandler' :: ExceptT ServantErr IO a }

have

newtype HandlerT m a = HandlerT { runHandlerT :: ExceptT ServantErr m a }
type Handler = HandlerT IO

?

I don't think it would break anything but it would allow easier writing of instances for classes that have either an overlappable instance or a default implementation for monad transformers.