He's a coach who made his bones in NY, and he deserves that, but he's had his fair share of losing, non-playoff seasons, and hasn't even won Super Bowls with teams from different decades, nor has he been an innovator in football, imo.
I'm not attacking him...though I've never liked him, I'll give him his props, but I say no way in Hell is he top 10.
Just off the top of my head, without even looking at a list to make sure I don't overlook anyone, I'd say George Halas, Paul Brown, Vince Lombardy, Tom Landry, Don Coryell, John Madden, Don Shula, Joe Gibbs, Bill Walsh, Chuck Knoll, Bill Cowher all rank ahead of Parcells in my opinion.
Jimmy Johnson, Bud Grant, Marv Levy get consideration.
But that's just me...there have been many many coaches in the NFL, so not putting Parcells in the freakin' top 10 all time is not a big deal. He won the SB with the same basic team, and has not won another one...being tough and helping teams become something better when they were mired in crap can be done by many good, solid coaches, but it doesn't make you top 10 all time, imo.