Idk how id feel about Foster at this point, but i dont know about the argument of other positions necessarily impacting the game more. Guys up the middle really cant be schemed away from.
An edge rusher you can run off the other tackle, or attack the space hes leaving behind or get the ball out really quickly. A WR you can bracket or put a lock down CB on. A team can move WR's around to avoid a certain CB (though adding one here would give us good CBs all over the place)...
But having two stud ILB's can have an impact on literally every play... whether blitzing up the middle, tackling ball carriers from sideline to sideline, covering RBs, TEs, and slot receivers, etc....
Safeties can cover the whole field, prevent the big plays, come down and stuff runs, blitz to add pressure, cover TEs, etc...
Same with interior DL... quickest way to throw off a passing game is pressure right up the middle. QB cant step up into throws and it gets there much quicker so harder to just avoid by getting the ball out quick. Also destroys a run game when the RB's are getting hit 2 yards behind the line every play.
Same then obviously applies for interior OL, to avoid allowing another team to do to you what i just described above.
I am a firm believer that the best way to build a team is through the middle. And i think a dominant DT, ILB, S, or C/G will impact a team more than a great WR, TE, DE/OLB or CB can.
Obviously it's important to have talent everywhere, and ill take an all pro edge rusher over a good starting OG.... but all things equal im going with someone up the middle.