Granted a lot of multichannel material sounds hokey, but then a lot of two channel stuff sounds hokey, too. There are factors bigger than two, three, four, five, six, or seven channels that affect the quality of the experience.
For excellent stereo, some of the better speakers I've heard require a complex set-up regimen in a well-conditioned room to sound their best. Then they require the right audio chain feeding and driving them to maximize their performance. Once achieved, however, the stereo sound is mind boggling compared to what we usually hear in our much less than perfect rooms with our much less than perfect systems.
In the realm of multichannel sound, the variables are even more complex and the set up regimen is even more daunting. The room itself becomes more difficult. The audio chain has increased demands as well, and its components are even more critical to overall success. When fully realized, it makes stereo a quaint, nostalgic experience.
One of the things I admire about some speaker brands, JBL and Revel included, is the relative ease with which one can create a decent to very good stereo and multichannel experience with some of their stock systems. Trying to do the same thing with other brands (Bose, Paradigm, Sonus Faber, and MartinLogan come to mind) is fraught with frustration and disappointment for those who want a truly balanced and "accurate" system. These brands can sound "impressive" in stereo to many people, but they cannot sound "right" in multichannel applications IMO, at least not without a lot of work.
While the set up and calibration that goes into a Synthesis system is beyond most of us, it's indicative of the kind of work that really should go into setting up a multichannel system. Of course, there are plenty of Synthesis systems that sound like crap because the installer took short cuts or was incompetent; or perhaps the owner insisted on foolish installation restrictions for aesthetic reasons. My personally set up and calibrated Performance Series sounds better than some of the Synthesis systems I've heard, but a properly set up Synthesis blows it away.
Multichannel sound is much more than just getting some extra amps and speakers, hooking them up to a five or seven channel pre/pro, and pushing an auto-EQ button. This haphazard approach will satisfy some and horrify others. In the late 90s, my first multichannel set up with a ProLogic receiver, LaserDisc player, some L7s, L5s, a custom center and a sub was very impressive to me. However, compared to the pre/pro, amps, DVD player, and Performance Series gear of today's system, it was an atrocity.
Stereo produces good sound with less effort. Multichannel takes much more effort. (Notice I'm only addressing audio here, not HT per se.)