http://sportsillustrated.cnn.com/football/2008/draft/teams/dolphins.html
Aren't Kendall Langford and Lex Hilliard still on the team?
1 1 (1) Jake Long T Michigan
2 1 (32) Phillip Merling DE Clemson
2 26 (57) Chad Henne QB Michigan
3 3 (66) Kendall Langford DE Hampton
4 11 (110) Shawn Murphy G Utah State
6 10 (176) Jalen Parmele RB Toledo
6 29 (195) Donald Thomas G Connecticut
6* 38 (204) Lex Hilliard FB Montana
7* 38 (245) Lionel Dotson DT Arizona
Read more:
http://sportsillustrated.cnn.com/football/2008/draft/teams/dolphins.html#ixzz1tA2Ecjvh
Honestly, it wasn't that bad of a draft all things considered. If you look at other teams, the majority of their draft class is gone after 5 years too. You are lucky if you get 3 guys from a class to stick around longer than 5 years.
At least in this draft, you had 5 guys who contributed something in the past few seasons. Even if Henne wasn't everything we wanted, he did contribute and win some games, so not a total failure.
Let's compare this draft with our rivals 2008 drafts. (still on the team in green)
Patriots:
http://sportsillustrated.cnn.com/football/2008/draft/teams/patriots.html
1 10 (10) Jerod Mayo ILB Tennessee
2 31 (62) Terrence Wheatley CB Colorado
3 15 (78) Shawn Crable OLB Michigan
3 31 (94) Kevin O'Connell QB San Diego State
4 30 (129) Jonathan Wilhite CB Auburn
5 18 (153) Matthew Slater S UCLA
6 31 (197) Bo Ruud OLB Nebraska
Jets
http://sportsillustrated.cnn.com/football/2008/draft/teams/jets.html
1 6 (6) Vernon Gholston OLB Ohio State
1 30 (30) Dustin Keller TE Purdue
4 14 (113) Dwight Lowery CB San Jose State
5 27 (162) Erik Ainge QB Tennessee RETIRED
6 5 (171) Marcus Henry WR Kansas
7 4 (211) Nate Garner T Arkansas (With Dolphins)
Bills
http://sportsillustrated.cnn.com/football/2008/draft/teams/bills.html
1 11 (11) Leodis McKelvin CB Troy University
2 10 (41) James Hardy WR Indiana
3 9 (72) Chris Ellis DE Virginia Tech
4 15 (114) Reggie Corner DB Akron
4* 33 (132) Derek Fine TE Kansas
5 12 (147) Alvin Bowen OLB Iowa State
6 13 (179) Xavier Omon RB Northwest Missouri State
7 12 (219) Demetrius Bell T Northwestern State
7 17 (224) Steve Johnson WR Kentucky
7* 44 (251) Kennard Cox DB Pittsburgh
Looking at this, you could make a case the Dolphins had the most successful draft out of our rivals that year.