I don't think this is correct at all. Sure, at forums like this people prefer stock Android, these are the same people that think a Quadrant score is more important than a phone's actual useability and who would get a semi because they got 1 more fps in a 3d test. For people who actually use their phones for more useful things Sense has many many advantages and I miss it at the moment.
Here is just one thread of the many forums out there that prove my point:
http://www.neowin.net/forum/topic/965704-sense-or-stock-android/page__st__45
And some people in there don't seem to be too knowledgeable on android as they just mention a launcher, which only replaces the homescreens obviously and not the actual system integration etc.
Plus I completely agree with you about quadrant and linpack etc. and just benchmarks in general for everything as they don't give any idea of real world usage (just check all my posts in the GPU section giving of to people about running 3D mark etc.
).
My samsung i5700 on a custom ROM feels just as fast and smooth if not a bit better than my bros desire on stock 2.2 yet his quadrant and linpack score are like 5-10 times higher than mine and another post indicating this as well but compared to the HTC incredible S:
http://forum.samdroid.net/f21/testing-new-htc-incredible-s-device-4630/
Plus I am on a kernel at the minute which gets no where as high as another kernel but it feels a lot quicker and smoother to me than the one with a higher benchmark and plus it is more stable as well.
Benchmarks are the most useless things ever especially for GPUs
I love customization and the choice of having what I want hence why I prefer stock android as it is lighter, not bloated with features that I would never use, many more choices on CM ROMs, which for me are much more useful than sense stuff and as I mentioned before I honestly think that there are many 3rd party apps out there on the market that are better and nicer looking than the sense stuff at default and even better after about 5-10 minutes of customizing it to your liking.
e.g.
Dialer - Go contacts, dialer one, touch dialer
SMS - handcent
(too bloated now), go SMS pro, chompSMS
Browser - Miren, boat, dolphin HD and mini, xscope
Launcher - GO launcher, Launcher pro plus, ZEAM, ADW ex and the full one
Widgets - all of the pure calendar widgets, LPP widgets, smooth calendar
Weather app/widget - snowstorm, Go weather, palmary
Email - K9
(not too sure about email apps as I don't use any of them, just gmail)
Gallery/video Apps- Quick pic, mobo player, Vplayer, rockplayer
Music apps - PowerAMP, winamp, cubed, doubletwist, playerpro, 3
Camera Apps - camera 360, vignette, retro camera
Keyboard - Gingerbread, swiftkey, thumb, swype, smartkeyboard
And there are many more apps out there that IMO are better for looks/UI, functionality either free or paid, most of the ones that I mentioned there are free as well.