Just finished the game yesterday.
I wanna say that the best area is without a doubt archdragon peak. Such nice scenery and totally different from the rest of the game with its darker atmosphere. I almost missed this area too if I hadn't checked a guide.
First time in awhile I felt "full" after beating a game. This game was well worth the $60 I paid for it because it had a ton of content and secrets. I was very satisfied by the end.
One complaint tho: a lot of old enemy setups and areas make a return. Like, literally. They reused a lot of assets which is normal, but they really couldn't think of anything new in some instances. I felt like I saw a lot of these old tricks before.
Mimic chests
Troll illusory walls
Dragons... On top of buildings.... Again.
Enemy ambushes were all predictable.
. Jesus Christ.
Archers. Really? Again? The same setup?
Poison swamp. Again....
Dragons.
Lol and they made sure you couldn't Poison any dragons this time around for an easy kill. You had to work for that!