International level is no different to premier league, club football is a higher level than international, the quality is higher, the competition is tougher.
Wilshere was pretty much Arsenal's best player in the games he started or came on as sub, which is standard for him. When he's fit he's one of the best players for Arsenal and one of the best in the league. The other thing he's consistently done is when played he plays near his best instantly, and he's come back from a lot of injuries, he might not play for long before another injury but he's someone who can come back playing at the top of his game right up till he's out for the next 8 months.
Drinkwater's starts really mean nothing, I genuinely like him but Kante makes that midfield and Drinkwater in a different system didn't seem nearly as comfortable or effective, ultimately he's just not as good as Wilshere and I'd take Wilshere over Drinkwater easily. Now if Wilshere had come back in terrible form that would be a different situation but he looked great for Arsenal and there is no reason to believe he can't continue to play at that level.... again right up till he gets injured again.