To clarify; I think they tried to "do a Wii" on GH:WT, so not poor intentionally - more to be as casual as possible to appeal to as wide an audience as possible - but poor from the established fanbase, which expected more rock/metal and less Willy Nelson.
The track list seems designed to be wide yet inoffensive; even band names and lyrics are inoffensive. No Suicidal Tendencies, no Lamb of God, even the Ozzie songs are Ozzie,
not Black Sabbath - yet every (main) game till now has had Black Sabbath on it, and there are loads of excellent untouched Sabbath left. Make it appeal to mom and pop, and the whole family can sit down for a sing-a-long

The established fanbase was meant to buy the DLC (as rabid brainless cash cows) for what they really wanted.
Capt Speedy said:
Well if that is their plan, it ain't working so far.
Which restores a tiny bit of my faith in the average gamer. How we spend is the only way they really listen to us...
This is just my (paranoid) conspiracy theory of course, but how else explain the radical departure of songs lists from GH1/2/3?