I was disappointed in the finale as well. Tho Sheen made the show, I don't hate Kutcher like everyone else. I watched off/on but for my taste, show was sometimes a little "raw"/risque)" for my taste.
That being said, it was also very very funny at times. I always hated the Rose character. I found her unfunny and annoying and as soon as I saw her face, I knew it wouldn't be that good.
I too was expecting Charlie to show in the end. Like I said, it was a disappointment.
TIS