Yes, I would agree that frequently many teams outside the Top 4 make the Final Four. Taking this year as an example, Villanova is the only team in the Final Four, that is clearly in the Top 4 by any computer metric you look at. Kansas falls into the Top 4 in most. Michigan is in the top 4 in some (as high as #2 with Massey, as low as #9 with Sagarin). Loyola is not Top 4 in any. And, many years there are 1-2 Loyola's in the Final Four.
My only notation, was that when its all said and done, if Michigan, Kansas, or Villanova win, they will likely be in that Top 3-4 of all the key computer metrics. That has been the case 11 of the last 12 years, with 2014 UConn being the rare exception. Since 2006 12 teams have been a 5 seed or greater in the Final Four. 1 has won the title.
It was interesting to me that 3 of the last 4 Final Four runs for Michigan State were as 5 seeds or higher. Would not have guessed that.