I'm just not sure that's something most players grow out of
Eh? It's the norm for young players to be inconsistent and improve in that respect as they age. The difference between a 17 year old Messi and a 27 year old Messi is not technical ability or a even physicality, but the mental maturity to produce it week on week. The same applies to every footballer.
I'd heavily wager that we don't see an improvement as such from Phil (as in doing 'better' things) just that he will take what he has done in his best games and do it on a far more regular basis, the way Silva, Hazard and Sanchez do. The boy is arguably the most naturally gifted footballer in the league, and once he starts proving that week in week out, football is going on start sitting up and taking notice of this lad. He's a future ballon'dor winner, and a POTY award is not far away for him.
Other than that, I think Ibe will thrive with more game time and his pace will be a real asset seens Coutinho, Lallana and Firmino don't really provide that. Clyne will dominate his flank in most games and be one of those that we love whilst other fans wonder what the fuss is about.
Firmino for me will show moments of brilliance but may take a season to become consistent and Lallana will be unspectacular but actually contribute very well in terms of numbers.
Milner I think though will be our best signing. It will be like having a 27 year old Gerrard-light in the squad. He'll lead by example, do his job immaculately and take ownership of games. Think despite being a similar player he will have a big effect on Henderson who will flourish with a more mobile partner.
I think as long as we get a one in two forward with pace most importantly our whole squad will suprise everyone.