Man, I have to be honest here, I played up through Day 3 in this game over the weekend and...I actually like it. :\
This is a not a good Ninja Gaiden game, but I knew that going in. Taken on its own merits, however, I'm actually finding it to be a fun, cinematic brawler with some serious energy behind it.
The fact that this game is considered complete garbage shows just how much higher our standards are, however. I picked up a huge stack of Dreamcast, Saturn and PSX discs this weekend for $6 (no cases) and tried out a lot of games that I had previously been curious about. Most of these were pretty average (or below average) back in the day (though I did get Astal for 25 cents). In 2012, however, they are bad to the point that I wonder how they were released at all. When I jumped back to NG3 after all of this it felt like the finest game ever made by comparison. It's really stunning how much better today's average/crap games are compared to what was considered average 13 years ago.
Don't feel bad. I actually went ahead out of perversity and gave this a shot. It's not a bad game. As you say, it's a fun brawler and it sure as hell has a lot of energy behind it. However it does feel incomplete - as if the free DLC weapons they're adding were meant to be in it, etc - stuff like that.
It's not a Ninja Gaiden game, or really a traditional Japanese style action brawler like DMC, Bayonetta, etc. They definitely wanted to try and make a westernized casual fun brawler. But, it is fun. Its production values are pretty high for the genre, though it's no God of War 3.
It's also a very good point that the standards for an "average" game today are far higher than ten years ago. Average games from the past 2 generations or so, when 3D games in general were still crude and designers were figuring out the basics, are really bad by today's standards.
Today, you have to WORK to make a truly bad game. You have to be truly incompetent at every level, and despite all the insults calling Hayashi "Hayashit" in this thread, Team Ninja is still competent post-Itagaki. They can put together a good game that hits all the basic marks and checks the boxes.
But yes, yes. It's nothing like a "proper" Ninja Gaiden, tho that seems a conscious choice as much as the team being literally incapable of making anything like a hardcore game.
If they refocused on the hardcore tradition for NG4, they could probably make a pretty good game. Anything like Ninja Gaiden Black is probably out of the question, the team is just too different now and that's not even counting Itagaki.