One of them played a key role in a team that won the league, the other two spent most of the season injured.
I know who I would take.
Not really a key role is it. Vardy, Mahrez, and Kante were their key players then their back 4. He had a very specific and very limited job in that Leicester team that doesn't exist in this England team People who think all of Leicester's squad are suddenly world class are presumably the same type who were complaining when someone like Cleverley would get picked just for playing for Man U, even if they won the league. Both were wrong.
Wilshere's so much better, so much more talented than Drinkwater its not even funny. If Arsenal had the chance to swap Wilshere for Drinkwater do you actually think they would? Of course not. If he's not injured currently it makes absolutely no sense to not pick him. A lot of people let personal dislike of Wilshere cloud their judgement. Talent wise he's nearly unrivaled in that squad. The team doesn't lack for triers in midfield, it does lack for genuine quality on the ball in midfield that Wilshere offers.