First and foremost, I have to call your attention to an article written by Rich Hoffman in the Daily News that addresses the Eagles' ability to draft. There seems to be this meme out there that the Eagles are one of the poorer drafting teams in football. Frankly, that's just not true. In fact, Hoffman points out that the Eagles(in the Reid/Heckert era) are in the top 5 of pretty much any method you use to quantify how good a draft was.
Now, the simple fact that the Eagles have been so successful in the Reid/Heckert era(2002-2007) should be proof enough that the drafting has been pretty good. You simply can't win that much and not have drafted well. Yet for whatever reason, the meme that Reid can't draft gets propagated anyway. If you think about it, Reid/Heckert have only had one first round bust. That was McDougle, who was never healthy enough to actually play. He's still a bust, but we'll never know if the talent evaluation was correct or not.
Where the real failings have come and where you really can criticize the front office is in free agency. I would suspect that if Rich Hoffman were to compile a list of free agents signed by every team in the last few years and gauge their effectiveness, the Eagles would not be nearly as good in that dept as they are in the draft.
Let's just look at free agents brought in the same time frame(2002-2007) that Hoffman analyzed the draft...
Ian Scott - Never played; Contributed nothing whatsoever
Montae Reagor - Only active for 5 games, contributed next to nothing.
Kimo Von Oelhoffen - Only active for 8 games, contributed 2 total tackles(ie: nothing)
Kevin Curtis - Good signing, probably exceeded expectations.
Bethel Johnson - Didn't make the team
Darren Howard - 6 year, $30 million contract for 6 sacks in two years. Lost his starting spot in his first year.
Jabar Gaffney - Didn't make the team
William James - Demoted to 4th corner this year(if that)only active for 14 games.
AJ Feeley - Ok at best. Played in 3 games since he returned, lost both starts and threw a total of 8 INTs.
Ed Jasper - Didn't make the team
Jeff Garcia - Good signing, led the team to the playoffs and won a playoff game.
Matt Schobel - Caught 25 passes in 2 years and even when the starting TE was injured a rookie TE(Brent Celek) started over Schoebel. Has contributed very little.
Shawn Barber - Only played 13 games and was a backup.
Juqua Thomas - Has probably exceeded expectations.
Mike McMahon - Horrible. Had a QB rating of 55.2 in the 9 games he played.
Not much else in 2005.
Dhani Jones - Had a good 04, but downhill from there. Signed a 5 year deal and was cut before this year.
Jevon Kearse - Signed an 8 year, 60.6 million dollar deal. Never registered more than 7.5 sacks, missed all but 2 games in 06 and was inactive or played very little for most of 2007. Will likely be cut this offseason.
Jeff Blake Backup QB, never really played. Not a big deal either way.
Dorsey Levens - Actually had a solid year in 04 in a backup role.
Hugh Douglas - They brought Hugh back, but he was past his prime and had just 3 sacks and started 3 games.
Jon Ritchie - Was ok in 03, but played in just 3 games in 04 and was gone.
Nate Wayne - Signed a 4 year deal and was let go the next year. Was average in 03 and played in only 9 games in 04.
Blaine Bishop - Signed a 3 year deal, lasted one year where he played 12 games.
Levon Kirkland - Played in all 16 games, was painfully slow and retired at the end of the year.
Antonio Freeman - Signed a one year deal. Caught 46 balls and 4 TDs
These were simply free agent signings. I didn't include practice squad or NFL Europe guys. I didn't include undrafted rookie free agents. I also didn't include trades like Terrell Owens, Donte Stallworth, or Mark Simoneau. This list was simply veterans signed as free agents from other teams.
In short, it's not very impressive. In fact, it's hard to find one real home run hit out of that bunch. The closest they've come is Garcia who had one good half season and Kevin Curtis who exceeded expectations in his first year but isn't exactly a pro bowler just yet...