Genie,
If changing a chord from a C to a Cmaj7 is jazzing it up, then it's mild jazzing. **G**

If I really wanted to jazz it up I'd play it with these changes:

(Cmaj7) All of me,
Why not take (E7) all of me (E7#5),
(A7) Can't you see, I'm no good (A7#5),
Without (Dm7b5) you (Dm7),
(E7/Bb) Take my (E7/G#) lips,
I want to (Am7b5) lose them (Am7),
(D7)Take my arms (D7b5), I'll never (Dm7) use (G7#5b9) them

(Cmaj7) Your goodbye,
Left me with (E7) eyes that cry (Bb9),
(A7) How can I, go on dear without (Dm7) you
(F maj7) You took the (F#dim) part,
that (Em7b5) once (Bb9) was my (A7b5) heart
So (Dm7b5) why not take (C#maj7) all of me(C).