But Shinobi on the Playstation 2 sold very well... It was SEGA's second best selling game globally that year if I remember right. Ninja Gaiden didn't even come out until 2004, Shinobi was out long before it. Whilst Devil May Cry is more of a stylished based combat than anything else.
Kogen pretty much said what needed to be said, Joe Musashi's primary weapon only becomes his sword when he gains the powerup, and even in the original he had an unlimited supply of surikens. The game could easily be called a run and gun platformer than an action game. Would Shinobi sell if it was changed into a primary combat based? Most likely, would SEGA do it? Quite possible. But using that excuse can allow anyone to justify change in any franchise in SEGA's catalogue, you can say SEGA did the right thing with Sonic Heroes as they appealed to everyone and it became the best selling Sonic game since Sonic the Hedgehog 2. You can say that since Shining Force is selling better now, SEGA did right to change the art direction and so on.
But I agree with Sanus, what is the point of bringing back the IP if you are just going to change the fundamental principles? Just make a new series, call it Blood or something and about ninjas. If you are not going to follow the premise the original was based on, I see little reason to bring it back, outside of being a cynical attempt to cash in.
And no, Shinobi on the Playstation 2 wasn't a good example, it really could be a new series, the main character is different, the gameplay is set towards the hack and slash crowd and you are forced to fight several baddies, especially to charge up your sword.