Sorry. I see now, that wasn't what you asked
Hmm.. there are both some valid and some rather strange debate points in the "are-birds-dinosaurs?" discussion.
Most paleontologists supports the evidence in favor of birds being descended from maniraptors (dinos such as oviraptors, troodons, and dromaeosaurs)
Bird expert Alan Feduccia is among the few scientists who make (more or less) valid points against this. He agrees that birds are archosaurs (and therefore related to dinos, crocks, and pterosaurs) but denies that they are maniraptorian dinosaurs. He believes that dinofuzz on the back and tail of Sinosauopteryx is remains of a lizard-like frill. He claims that the hand bones of birds are different from those in dinosaurs. (a debate about what number to give them and when they arise during fetus development)
Another valid point is that the Archaeopteryx fossils are older (late Jurassic) than most maniraptor fossils (mostly Cretaceous). If Archie' and all other birds are derived maniraptors, there must be a lot of maniraptor fossils waiting to be found in layers older than 150 million years. Only a few maniraptor fossils older that that are known so far.
(Good fossils of small bodied dinos from the Triassic and Jurassic periods are generally rare, so no matter if Fedducia or the rest of the world’s paleontologists are right, we still lack the fossils to show one or the other)
An Italian dinosaur called Scipionyx samniticus is known from one very well preserved fossil of a juvenile. Parts of the internal organs are preserved, but no dino-fuzz. Skippy's closest relatives are believed to be fuzzy, so a great discussion concerns whether this fossil contradicts the dinobird concept. I see no problem since many dead animals loose their hair or feathers when they float around in water. And the anoxic conditions believed to have preserved Skippy's intestines could be different from the conditions outside the body.
One of the strange points against the dino-bird connection concerns a fossil called Protoavis texensis. The paleontologist who found it claims that it is a Triassic non-dinosaurian bird, but the few other scientists who have been allowed to see it, says that it is a 'chimera' - a mixture of bones from different species of animals. And that it is so crushed, that it takes a lot of imagination to claim that it looks like anything.
Other strange claims include, that all of the many, beautiful Chinese fossils of feathered dinosaurs are false.
Some claim that the maniraptors are in fact ancient birds and not dinosaurs. Others claim that Archaeopteryx is a dinosaur, but that real birds are not and are descended from a different lineage.
Also, one problem with your question about "the main points that generate disagreement" is that people who doubt the connection between birds and dinos often cling to just one, individual point and disregard the multitude of evidence in favor.
or gliding from tree to tree ("tree down"
