In many ways, the introduction and conclusion are the hardest things to write in the dissertation. Not only do you have to be clear about your main points, but you also want to interest your readers and compell them to keep reading (in the case of the introduction) and make them feel a sense of accomplishment and increased knowledge (in the case of the conclusion).
As they say, no pressure.
I found it very helpful to read some of the introductions to my favorite scholarly books before starting my introduction draft. I didn’t do that before I wrote the conclusion.
My last three pages of the conclusion are, at the moment, truly lame. I felt like I was trying to get out of an awkward conversation at a party as I was writing it . . . I babbled on and then ducked away suddenly. The last pages string together some vague platitudes and maybe even a little motivational speaker-ese. Yuck.
I’m going to read the ends of a bunch of good books today. I think it will help.
Becoming Doctor Jones 
Go for it, ma’am. I suggest rewriting until what you’re saying scares you just a little bit. Let your advisor tell you it’s too much! :)
get a third party to view it… conclusions should sum up well !
good luck !