Looking over this further on my lunch.
Quick thoughts.
Book Quality - Its a USA printing. A lot of my other ones seem to be China. The paper seems pretty poor/fragile? No tears yet as its brand new, but honestly feels like it wont last if I dont baby it. (Note: My Dragonlance trilogies of Chronicles and Legends, are still in great shape...and its been like 30 years...)
Elegy - I like this a lot. Sets a cool hook for the book.
Fizban Notes - Eh, not as cool/funny as Xanathar, sorry Fizban.
The First World - I like this. I like the suggestion of what it could be, and I like the description of dragons as 'knots' of magic. I think that's later in the book.
Other worlds, as long as it doesnt step on any pre-existing lore, what I have seen so far is good high level overview stuff.
Character Creation - I've complained about this elsewhere already. 1 Page too long.
SubClasses
Monk - I feel Pathfinder did this better, but I'm sure Pathfinder lifted it from a 3.0 prestige class or something anyway...
Ranger - Fine. Now that I look at it, you cant take a Gem Drake pet that does psychic damage. Too bad.
Feats - Only 3? I miss the days of many many many feats.
Spells - A few interesting ones. Stride being discussed elsewhere looks cool.
Items - Cool. Love me a Dragonlance.
Horde Items - I like this. The concept of Dragons as being's of Magic, infusing their Horde and powering up items.
Gifts - Cool, again, I wish 5e did more with stuff like this that wasnt optional but thats a 5e thorn thats starting to annoy me.
Dragons in Play
This is where the book starts to really shine in my opinion (its also where the 'Knot' reference is, page 40 under Death of a Dragon).
Tons of ideas, hooks, references to undead dragons, echos (from the original Elegy conceit of the book) Gods and Religion, tons of good stuff in here to me.
Rules on creating Hordes, closes out that section, then we get to the Lairs section, for each of the 'main' dragon types, and a few extra types (5? looks like it). Probably my favorite section of the book at a glance.
Some monster profiles then wrap things up for various types of 'non-dragon' stuff.
I really like the format, and outside of some systemic complaints my only real issue is I wish the stat blocks for the metallics and chromatics were in here, so it was a one stop shop for Dragons.