1) A properly adjusted drivetrain doesn't need to smooth out. It's already smooth.
2) Maybe. When shifting the front, to a bigger ring, for example, it's necessary to hold the lever for a moment while the chain starts to shift before letting it go. You also have to learn how to trim the front derailleur.
3) With a triple on a bike with short chainstays, yes, you may have that problem at the extremes. However, it really, really sounds like you were testing bikes that were very poorly set up.
Training: 2002 Fuji Roubaix Pro (105 triple)
Commuting/Daytripping: 2001 Airborne Carpe Diem (Ultegra/XTR, touring wheels)
Commuting/Touring: 2000 Novara Randonee (Sora/Tiagra/LX, fenders, lights)