Not necessarily true. The choppy idle comes from valve overlap, mixture and timing tuning, as well as duration. And there is easily such thing as too big as well. Either it will put you out of useable powerband, or in the instance of stock heads, exceeding a certain valve lift above where port flow stalls, you're going to see very little power improvement even at the top end.

Doesn't make sense to get 5hp on top to loose 50ft-lbs on the low end. Or have a cam that's going to peak power out at 6500rpm when your shift point is a 6000rpm. Or trying to come out of the hole with 2.73 gears. The whole system (all the engine components, the gear, torque convertor if applicable) all has to be matched.

Let me give you a story based on true life from a few years ago. Two co-workers, I'll call one Mr. Big, and the other Mr. Science.

Mr. Big, of course always went big. He built a car with the help of a fellow "go big" guy.
Engine 540ish ci Chevy BB with roller cam exceeding .7", Holly Dominator, 14:1 compression (not kidding, he probably could have run diesel, lol), aftermarket heads hogged to the max with over 400cfm on the intake, and huge Flowmaster exhaust. Rest of the combo was 4000 stall covertor, 4.11 rear gears, 12x33 slicks, with a line lock. He rarely drove the car on the street (super loud, sucked race gas by the gallons, anything above 50mph will drain you.)

Mr. Science built his as essentially a pro-tourer in the true sense. Handling, braking, comfort, and power. His was a 400ci Chevy SB 0.30" bore. He picked his heads not only based on flow, but as runner volume to ensure good velocity, and considered the combustion chamber. He injected it, and had a roller camshaft that probably didn't exceed .55" lift. Compression was about 10.1 and the car would use 91 Octane no problem. He carefully chose all the components of the engine right down to the 3" exhaust with crossover. Trans was a T56, and gearing was 3.73s. He would switch to 15" drag radials when he went to the track. Idle was definitely not stock, but still smooth. Keep in mind the suspension was dialed in for handling, not for maximum 1/4 mile traction.

One day, we had an outing and both came. Mr. Big had to tow his. Mr. Science drove his. To keep the story short, Mr. Big was running 11.20s, Mr. Science 11.50s. Only .3s difference yet Mr. Science hadn't even the right suspension. His car you could drive across country and get over 20mpg on the freeway (he measured it several times driving 30miles one way to work where most of it was freeway). His was also more reliable (Mr. Big was always breaking stuff). BTW, both of these were on the motor only, neither had nitrous installed.

If I had to choose one of the two cars to own, it would be hands down Mr. Science's.