Thing you should fix:
You forgot to add the hero glow to the hammer.
The arms intersect horribly with the shoulder pads in most animations, this will require some animating that might be difficult.
Add in some pupils, the paladin and Arthas's textures have some, it will make his eyes look less possessed mad man and more human.
The cloak starts out suddenly from the middle of his back, that looks weird.
He has iron pants, that must be hard to move in, but they do offer awesome protection for his junk.
Make the wings on his helm better - more detailed.
The lower mesh of the fore arm intersects with the upper mesh - it is visible even in the screen shot of the model - leave a little bit more distance between the two meshes.
The small parts of the cloak are connected to the bone of the arm - that is very weird.
Add some sort of trim at the end of the cloak and maybe to its sides, it will make it look better.
I suggest using the wings of the blood elf glue-screen texture for the wings on the shoulder.
Make the book a bit smaller.