First, welcome to the DIS, Brytsun.
I have seen CP every year sine '99. It is a highlight of every December trip. You can see it without the dinner package, but the package makes a nice evening of it and does give you better, confirmed seating. One point to remember in the dinners, is that it is all inclusive, appetizers, entree and dessert, so if you were ever wanting to eat big, it is a pretty fair deal.
As for reservations, not can be made, only the dinner package. And I would say it is a must see, yes.
This site will answer a lot for you.
http://allearsnet.com/tp/h_cpfaq.htm