Addressing peoples points in no particular order:
Graduated timing windows are very useful for measuring true skill in a rhythm game yes, but for games like guitar hero the point of the game is not to hit the note with precise timing but just to hit the note. Comparing to DDR is not truly possible as the games, although both rhythm games, have completely different aims.
DDR vs. GH/RB:
DDR is meant to be highly competitive, either against yourself (trying to beat your last score), or against other people. I can almost guarantee that there is a high percentage of people who play songs on DDR not because they enjoy listening to them, but because they are considered hard to play/beat/get a high score on/etc (this is not to say that no one enjoys listening to the difficult songs). There are a couple reasons bad step charts exist: the main cause is people want to play the songs they enjoy (but have little skill making charts) but can't find a chart for their favorite song so they make one, or someone just wants to make a chart for a random song for the sake of making a chart (I know I fall into the previous category, minus the chart making).
(Include Rock Band in this section as well, as Guitar Hero and Rock Band are very similar) Guitar Hero's aim, on the other hand, is for people to play the songs they like hearing (the reason for so much DLC) and to simulate playing them on an instument (how ever poor of a simulation it may be). To this end the binary timing structure works very well (simple hit/miss structure). The goal is to hit the correct notes with some accuracy, not perfect accuracy. If you think of playing an actual guitar (or other instument), the average person is not going to notice that you (the music expert, for arguments sake) are play some notes 0.1 seconds early/late as long as you are playing the right notes. Guitar Hero has become a competitive game because its players have made it so, and even if you do not want to compete you can still enjoy the game.
DJ Hero vs. Beatmania near the same argument as DDR vs. GH/RB. Although I have not played either extensively (one because I don't care much, the other because it is not out yet), I can tell you from my experience as a gamer (rhythm games and more) that they each have their own niche.
From the M.E.W.con forums:
OK I finally get it- Beatmania is all about getting so good at a song that you impress people and feel good, DJ Hero is all about having fun and playing it as a party game, THAT is the main difference between them. Granted DJ Hero has some songs that are hard to play just by looking at them but nothing compared to Beatmania.
Although I do not entirely agree with the impress people part, Mr. Slimero has hit the nail on the head here.
From the MEW Con forums:
When BeatMania came out, it was stupid for the same reason: pretending to be a DJ is retarded...
Neither this game nor BeatMania accomplished, or even tried to accomplish any of these. The reason is because that would be work, and nobody wants to play work. So, BeatMania settled to be a challenging game where the player focuses on essentially playing the music. It's not about being a DJ; the controller becomes a dynamic musical instrument.
DJ Hero is trying to simulate
a few aspects of being a DJ. Fully simulating it would involve a massive controller that would be hard to play let alone understand. BeatMania has settled on being a challenging (competitive) game, where as DJ Hero is settling on being a party game.
In the end you can not compare DJ Hero Vs. Beatmania and Guitar Hero Vs. DanceDance Revolution (and Guitar Freaks for that matter) because, although they fall into the same general category as rhythm games, they are different types of games (party games Vs. competitive games). It is the same as comparing Rock and Country, although they are both music (and they use some of the same instruments), they are different
types of music.
For the record: I enjoy both DDR and GH/RB, and am looking forward to DJH.
Also, if you are going to debate games (or anything for that matter), do it in an intelligent manner, not "This game sux/is crappy/terrible/poor/cheap/etc.", instead "I don't like ThisGame for A, B, and C reasons (
actual reasons, not my earlier example), and I feel that ThatGame is better for X, Y, and Z reasons (again
actual reasons)" remembering the entire time that this is all a matter of opinion. It is also a good idea to avoid attempting to compare dissimilar things (DJ Hero and DDR, World of Warcraft and Final Fantasy (not counting the MMO's), football and basketball... otherwise known as This Subcategory vs. That Subcategory of the same general type).