"I've commented before on my belief that the era of conventional parachute operations could be coming to a close with the advent, and perfection of tilt-rotor technology."

I disagree.  I will explain further on.

"The V-22 has been a problematic during its development phase. But arguably no more so than some other aircraft that have subsequently proved their operational worth. And now that the Osprey has deployed to Iraq, I suppose we'll see."

I agree.

"But if teething problems of the Osprey are worked through in the coming years, and the onward march of mechanical, avionic and materials technology takes tilt-rotor a viable concept, then it will strike at the heart of the raison d'etre of parachute infantry."

I disagree.  I will explain further on.

"And sooner or later I think it's inevitable that the problems of tilt-rotor technology will be things of the past."

I agree.

"And the tactical superiority of a four engined C-130 size tilt-rotor that could travel inter-continentally and put troops down on a dime would undeniable and irresistable."

I agree.  For certain situations.

"So as impressive as the legacy of the 82nd's WWII combat jumps are, parachute infantry will inevitably, I think, join horse cavalry in the pantheon of glorious, yet obsolete military technologies."

I disagree.  I respect your viewpoint.  Your position is well thought out and articulated.  I'll begin my rebuttal, trying to be as sincere and thoughtful as you have been.

I believe tilt rotor technology will be a huge success and that it will make parachute operations more relevant than ever, both strategically and tactically. 

For example, tilt rotor technology will solve one of the problems of a parachute raid: extraction of the raid force.  The prime recent example is Kandahar.  The Ranger raid force was inserted by parachute and extracted by helicopters after the DZ was secure.  That's using two different types of aircraft for one operation.  With tilt rotor technology the same aircraft that drops the raid force can circle on station and extract the raid force after the DZ is secure.

Obviously, parachuting was not chosen for the insertion method at Kandahar because the objective was out of helicopter range, since helicopters were used for extraction.  It was chosen because it was less risky than landing big helicopters until after the DZ had been secured.

In spite of the fact that much is always being made about the disadvantages of a parachute drop due to the scattered nature of it, the inherent early disorganization has just as often worked to the attacker's advantage.  Being able to deliver larger numbers of troops pinpoint enmasse is good in theory.  That was the idea behind gliders too, yet the glider proved to be best when only a few were used for a "coupe de main" type of limited objective: Pegasus Bridge is a good example.

Sure an aircraft dropping paratroopers is vulnerable to ground fire and Stinger type missles; and ships are vulnerable to anti ship missles, and tanks are vulnerable to anti tank missles ,and Strykers are vulnerable to IEDs and RPGs, and troops are vulnerable to bullets.  All things considered, keep a large aircraft moving forward; not sitting in the assault zone for the time it takes for so many troops to waddle off the tailgate!

Helicopters are very vulnerable while unloading.  The U.S. lost lots of Hueys in Vietnam, and small helicopters seem do do better than larger ones in hot LZs.  They unload faster and get out of the LZ sooner.  The U.S. replaced the Huey with the Blackhawk for a reason: it was a better option for hot insertions than the Chinook, which was a reliable helicopter already in service. 

A C-130 sized tilt rotor unloading 60-70 troopers in a hot LZ is going to be quite the RPG target.  At least as vulnerable, if not more so, than a similar sized aircraft would be during a pass over the DZ.   And if you get one huge four engine tilt rotor hit on the LZ it might block any further insertion and extraction.