I take realism in high regards. I like this new style. It made me so immersed in the story that I didn't mind the lack of epic sountracks that the old titles had, not that this installment was completely devoid of soundtracks.
If you could make me not care about all the other aspects of the game, you've made a memorable game.
As for your question, the axe. It's something new and it's like I said realistic. blade of chaos's design is too anime for me. I love it but compared to the axe's design, meh.
however I'd prefer the axe in terms of moveset. I also dislike how the axe acts like the mjolnir. Like I said, realism.
Norse or Greek? As in GoW lore? It's too soon to tell. We are only on the first GoW Norse Mythology. Will wait after at least some DLCs.
Overall mythology? I'd say Norse. Greek mythology is basically just Zeus just wanted to rule to world so he can get laid. Odin is better. He wanted knowledge and that was his downfall.
camera style is better. I can see more details, although it is lacking of gore now. I wish enemies didn't disintegrate after they get dismembered.
I like the realistic approach more. It's relate-able and you can do more stuff with it. There is always room to go full god mode at any moment's notice so Kratos's previous title's movesets and the like would be more impactful and rewarding once it's pulled off (make the unrealistic stuff be like a reward)
RPG elements? like open world? yes. I can take in the atmosphere more rather than just reveal from the cutscenes.
It's only April, there are 9 more months left. I do believe that it truly is a very good contender and a high standards for everyone to top. My only concern is that it may become forgotten as it is a single player game. Although The Witcher 3 still managed to be GotY despite being in the same circumstances.