A few people have brought up this "issue" to me, and I've never understood the problem. Obi Wan and Yoda clearly meditate and perform some kind of Force trick at their death. That's why their body disappears. But their clothes do not disappear, just their body. Darth Vader is not much more than a suit with a couple man parts inside. When he gets burned -- they don't reveal what happens to what's left of Annakin's body until, lo and behold, his ghost reappears. Qui-Gon and the other Jedi, of course, have no time to meditate and do any Force tricks before they're struck down -- hence no "ghosts." Any contact with Qui-Gon is different, occuring from across the threshold of death in a unique way.

Why is this simple interpretation of what's already there incorrect?