Well you specifically lamented the loss of Cover Flow, whereas Cover Tile was much more practical. CF was pretty an' all but in reality showed very little information, CT solved that problem, but I still didn't use it on a day to day basis.
Do many people use their iPhone music player in landscape mode? I doubt it because the screen is too small and becomes cluttered with information. There are always some people on the outliers but OS design should cater for the majority. With the larger display of an iPad this isn't an issue hence landscape mode is available. I guess Apple agrees with me.
If you want a better music player try Marvis Music Player.