Let's talk weapons. I'll just list them in my preferred order and give some thought on them.
The axe is probably my favorite weapon in Nioh. The moveset isn't the most interesting, with a high stance quick attack into heaven and earth combo being so good the you could exclude most everything else, but it feels and is powerful. High stance is the way to go, with enough toughness (200) not to get staggered out of your attacks. The lack of unique axes lead me to respec to swords mid way through my first playthrough, but this thing is tearing up NG+ on my second guy.
Kusarigama is another high stance wonder, with a more useable low stance than axe. The con of this weapon is the slight delay when coming out of a square attack spinfest, but damn does that attack hit hard, and it destroys yoki horns without even trying. Reaper can be amazing, if that's your thing. Being a dex weapon makes going ninjutsu a no brainer, and it allows you to just dump points into dex like crazy and get twice as much benefit from it.
Dual swords has my favorite combo (god of wind 3, yes please) and nice skills (water sword, sign of the cross), but I just find the damage underwhelming. I guess if I were to use skills more the damage would be better, but whatever. All the weapons work in this game, I just prefer harder hitting ones.
Sword is probably the most balanced weapon, and like straight swords in Dark Souls, it makes the game pretty easy. It has all the moves you could need, and the damage is solid, but I find the lack of a god of wind type combo makes it the most boring weapon to use. Quick attacks and a kick is strong, but not that interesting. Absolutely reliable, and fairly dull.
I have the least experience with the spear, and that comes down to not really enjoying the style. It has tons of moves, range, and is strong (when not hitting walls), but I just don't get into spears in games. Loving the halberd in DkS1 is as close as I get.
Anyway, I love this game, I find 4/5 weapons enjoyable, but I do hope they double the number by the time all the DLC is released.