The problem I'm having with today's TOD is the question of what makes a sequel, as opposed to the second part of a series.
Back to the Future II, for example, was intended as part of a series, since they filmed it back to back with III, by gosh and golly. I don't consider it a sequel, therefor.
The Lord of the Rings films were always intended as a trilogy. They are all part of one story - I don't think of Two Towers as a sequel at all.
But with something like Spiderman II or the Batman films - are these sequels, or parts of a franchise? The line gets blurry fast.
And, imo, parts of a franchise being better or worse is a totally different subject.