[Haskell-cafe] Monad classes and FreeT

Dear Café, I'm continuing my travel through operational and free, and was wondering: which is the reason why there's no instance such as (Functor f, MonadReader e m) => MonadReader e (FreeT f m) included in the 'free' package? It seems reasonable to me to have those instances. At least, there's the corresponding one for MonadIO. Should Free be considered as some monad to have 'at the bottom of the stack' as IO is? Thanks in advance.