I am a proponent of the statistics compiled by FootballOutsiders.com.  Comments they've made about the changing fortunes of the Birds these past few years vs. the 4 NFC championship teams focus on the visually inferior ST play we've recently had.  Although you mentioned improved ST play could be a nice "wildcard," that might "decide a game or 2," you did not feel the import was there.  

Remember, those short fields we used to have thanks to Brian Mitchell?  The long fields we'd give opponents when Akers leg was stronger, and the coverage better, a few years back (same for punt team- Rocca was below average last year)?  Those 10 yard swings on each side of a kick really add up... They can mean a team needs that extra first down for a TD, vs settling for a FG.  Or the Birds, who were inept in the red zone last year, would have already been in the end zone rather than at the 10 or 12 yard line.  It's not about 1/3 of the plays on ST... it's the impact of ST plays on our offense and defense that carry so much weight... shorten the field... lengthen the field.  

Regarding our roster and DE... Trent Cole has a great motor, but do we need to play him every down.  Similarly, Abiamiri represents a high pick... but will he play 80% of the plays at DE?  Also injuries the last few years have the Birds reconsidering their depth.  Juqua Parker/Thomas and Abiamiri (at least so far) are run-down first DE.  It's not that Abiamiri won't be a contributor... I see him as a fine run-first DE with some ability to get after the qb.  I just can't see him developing into a premium sack guy (he was not that in college, either).  Parker/Thomas is adequate on passing downs, nothing more.  Darren Howard now represents some depth at DT, where the Eagles truly lack depth... he's an "emergency" DE only.   He's a hard worker, but has proven ineffective rushing the passer as a DE in Phila.  He's a DT, and he'll take up a roster spot as a DT.

Jimmy Johnson and Andy Reid have a rotation philosophy at DE.  I don't see the term "starter" and "backup" carrying the weight it does at other positions.  They prefer to rest guys, and keep the "waves" of fresh bodies attacking the opposing OL, not only to prevent wear and tear, but also to confuse opposing OL with multiple styles.  So, does subtracting Kearse (and Howard, who's now probably a situational DT) and adding Clemmons enable the Eagles to "close the door" on the DE position?  No way!  I still think Andy is drooling over Vernon Gholston, and, barring a deal for a #1 wr that could cost their trade depth, I see the Birds doing everything in their power to move up and get that kind of impact, game changing talent... especially if he slides to picks 6 thru 8.  By improving the pass rush, he makes the DB's better...

I DO agree with you about OT, and the need to acquire a guy here.  The plan this time last year was to stay with the steady Runyan/Thomas combination, with Shawn Andrews and Winston Justice representing the future at the position.  Although that does not have to change, adding a high caliber OT in a draft year rich in talent at the position screams Andy Reid.  Williams or Otah seem the most likely pick if the Eagles stay at #19.