I wish I could understand everything he's saying (I can only fully understand the last part, which is "Ayumi tatsu ga yoi, yuragi semaru kyoukai no hateito! KYOUKAI NO DISTANTO!")
I've briefly played NGS1, NGS2 and 3RE, and I felt that my main issue with the combat was that switching weapons completely interrupted the flow of combat. With NG4, that issue has been solved, and Yakumo's combat seemed to instantly click with me. I've heard that his design and combat was meant to get new players into the franchise, and as someone who's still relatively new to Ninja Gaiden, that idea has successfully been realized.