For some people, more realism or a better fighting system is more appealing/entertaining. Skip to bottom for tldr version.
Itagaki's response really doesn't surprise me. This is how he acts and what he does. I know how much he dissed on Tekken, and I even remember reading how he dissed on Devil May Cry 3 right to the lead designer's face way back in the day, in comparison to Ninja Gaiden. I like both games, though I am more of a DMC fan. I won't get into which of those I think is better since I think they're too different to really compare well. The only games I know of him admiring are the Virtua Fighter games, and even then I get the feeling he probably thinks he did it better.
Itagaki has a big ego, and it makes it hard for me to really take him seriously. At the very least I take anything he says with a big grain of salt. But I'll tell you what my experience with DOA has been over the years. I played 3 way back in the day when it came out. I loved fighting games so I played them all. I enjoyed 3, but I can't say it really hooked me. I felt like the characters felt too flat (haha, breast sizes, haha, coming from a VF fan). They really did just kind of seem like Barbie dolls to me, and I had a hard time investing much interest in them. My favorite character was Brad because he was the most fun to me. I liked some of the music too.
Moving on, I was really impressed when the release trailer for 4 came out. I got very hyped for it, but in the end the same sort of thing happened. I got bored with 4 really quickly, and the characters just didn't hook me. I liked Lisa, I thought she had a cool design. The stages were cool too, but it wasn't really enough. At the same time, I also felt like 4 was a little too weird for me. Not weird in a cool fun way for me either, just weird in a way that put me off. Worst, I feel like it kind of ruined Brad, and I stopped liking him as much. He went from a badass, fun loving drunken master to just kind of a drunk, pervy bum.
By the time 5 came around, I had lost interest in the series, and I never bothered with the Xtreme games. The inclusion of the VF guest characters intrigued me, but not enough. Then, Jacky was announced, and he's one of my favorite VF characters. So, I downloaded Core Fighters and gave it a try. I've found that 5 has hooked me like none of the past games really have.
Maybe it is formulaic, maybe I'm just giving into what what's mainstream, but I know what I like. Maybe I'm just here for the Virtua Fighters. Maybe it got less "anime." Don't get me wrong, I can sympathize with fans who don't like change. I'm a Devil May Cry fan. I don't think that 5 was such a huge departure from the series. I actually like the characters a lot more now than I did before, and I don't think too much had to be sacrificed for it. Tina's one of my favorite characters now. I still think that it relies too much on sex appeal, but at least the game mechanics are good. Too much DLC? Maybe, but you aren't forced to buy it, or even download the compatibility packs.
tldr I like 5 a lot and Itagaki just has sour grapes, though I do sympathize with people who liked the general style of the past games. I like DOA in general, but I don't like Itagaki.