I understand the sentiment about the number 11; however, I think #31 is more indicative of linebacker excellence.
Case for #31:
Andre Collins made 1st-team All-American as a senior.
Posluszny made 1st-team All-American as both a junior and a senior.
Conlan made 1st-team All-American as both a junior and a senior.
Case for #11:
Arrington made 1st-team All-American as both a junior and a senior.
Parsons made 1st-team All-American as a senior.
Bowman did not make any 1st-team All-American lists.
Perhaps the "double sticks" moniker is more flashy, but it's tough to say the LBs who wore it exceeded the play of those who wore #31. And the arguably 2 best linebackers to ever don the vanilla whites (Dennis Onkotz and Jack Ham) wore neither (35 and 33 respectively).
Don't mean to start a debate, just an old guy's opinion. Heck my favorite player's number (68) is basically an afterthought today, so I'm not really attached to a player's jersey #.