That's a huge exaggeration.
It's also humorous how you call this a quick cash grab, and then point me to the PS3 version of PD, which was also a cash grab. I'm not arguing that this was a lazy thing to do, I'm only saying that if you tout your game as a rhythm game, you make the mechanic a priority over everything else. When a rhythm game offers you custom speed, that's a good thing, and not a reason for you to think it has a problem with reading. There is no one size fits all when it comes to speed in rhythm games, and for SEGA to not recognize this, shows how little experience they have with rhythm games. You can argue that SEGA has had a long line of rhythm games, but really, the only good one to ever come out of that company was Space Channel.
Anyways.
Worked my way to Groovy Tune, and just from the OVA, I need not see any more. This is the best version. All Miki, all the time. Wonderful. 10/10.