well, ruben neves used to play for my local team FC Porto so i know his game quite well, and although he had a great evolution this past year i doubt he is ready for prime time. He isnt great at protecting the backline by himself, i see him more as a double pivot kinda guy, hes a bit slow and not really used to play with short passes.
Time is on his side but i dont know if he will ever be capable to play the dm position in a guardiola team.
edit: the best comparasion for him would be like xabi alonso, although his body is not as a strong as it needs to be. for now at least