The DOA games aren't really buttonmashers. The only thing that buttonmashers have going for them is that their moves are abit unpredictable, which makes it harder to counter, and makes it alittle harder to do more complicated combos. But they have a big weakness too. They often don't pay attention, and if you interrupt their "flow", you often set them up to lose.
EX: I often play as Bayman, and when I come up against people who buttonmash, and here what I do. Just back away, wait until they attack, and tap Y. Bam. Their stunned. Now I/you have a big list of options of what we can do now. I prefer the turnblade into air juggle, taking away half of their health. Or, if I'm feeling sadistic, hello dangerous driver/half boston crab.
However, a fighting game must also be able to provide a challenge in single player.Cause face it, it's a fact that some people don't have/can't get Xbox Live to play against other people. And often, it's not because they can't afford it, but that there isn't a fast enough service out where they live. Most fast internet services are centered around cities and towns, and the farther you are from one of these, often it's much harder/impossible to get a respectable internet service.
DOA3 and DOAU do provide a good challenge, and respectable gameplay. In DOA4 however, the AI is too inconsistant to be any good, ranging from a bag of bricks to, well, Alpha Kasumi. In fact the only complaint have about DOA3 and DOAU. in DOA3, the camera angle is horrorendous for the last boss fight. DOAU is the tediousness of the unlocking process.
And as far as skill, you do need skill to advance. In any of the DOA games, even using the cheapest people possible(Ayane, Jann Lee etc.) requires some skill, because even if you use them. if you have no skill, someone who does could beat your *** in.