Mrebo said:

xhonzi said:

Bester said:

11) "I will become more powerful than you could possibly imagine" and then........nothing.

I spent a few minutes searching because I recall a decent conversation on this point a little while ago. Not finding it, I will quickly summarize:

Ben's death catalyzes Luke. That's what he meant, and that definitely came true.

It's an interesting point but I always thought it was even simpler than that. By more powerful, I always assumed Obi Wan was telling Vader that he will survive death and have greater but unknown influence through the Force.

I think the soundtrack proves my point.