Lets not get ahead of ourselves. They are relegation battlers right now, they need transitional and gradual signings to improve their stature and reputation (do you remember Man City's first signings? I do, not glamorous), they will be attracting top club rejects after big paychecks and without much options in coming window or young up and coming talents ok with missing CL couple years. Only after they shown more and become better will they attract another caliber of players (they just hired Eddie friggin Howe lol, so lets take a break on the ambition talk).
For now, they should be lucky they are attracting Rabiots and Coutinhos ("the could be doing so much better" players have better options then current Newcastle). If you just take a gander at their championship level squad, you will see thats an improvement.