I don't have anything against the 350 small block - my '77 'Vette has one, and it should be there. However, go to any car show that has a lot of hot rods...and you will see row after row of different makes of cars, all with small-block Chebby engines. It's just rather boring. "Oh look! I've got a 350! I'm just like everyone else here, including those guys driving Fords, Dodges, and Hudsons..." A hopped-up 6 will get attention, just for being different.
Cubic inch for cubic inch, an inline 6 will produce more torque than an V engine of the same displacement and technological advancement. If there wasn't something to the design, BMW and Jeep would have abandonded it long ago, and GM wouldn't be going back to it.