Here is an elaboration of the basic ideas listed in the right sidebar:
The current mainstream thinking is that birds developed from coelurosaur dinosaurs. I propose that birds did not develop from any kind of dinosaur, but rather that birds developed from pterosaurs.
I propose that long-bony-tailed basal pterosaurs (eg. Rhamphorhynchidae) developed into long-bony-tailed feathered flying basal Paraves (eg. scansoriopteryx). Which then developed into short-tailed feathered birds (Pygostylia). Which then developed into modern birds (Neornithes).
Let's look at what would be involved in a transition from basal pterosaur wing to basal paraves wing. The analysis shows the following:
1. The wing membrane would need to retract toward the wing bones.
2. The pterosaur long wing finger would need to shorten.
3. The pterosaur protofeathers would need to develop into pennaceous feathers.
4. The pteroid bone would be lost.
Altogether not a great amount of change.