The shooter mechanics still svck for 2 reasons:
1. There's hardly any sensitivity difference whatsoever between aiming down the sights and hip-aiming. I'm not aiming down my sights because I like the look of the prongs better, it's because I want to fine-tune my aim. The only way I can actually do half decent in non-VATS firefights is to actually turn the sensitivity down, which makes it painfully annoying to look around outside of combat.
Why should aiming down the sights of a weapon reduce the sensitivity of looking around? For me I play on the highest sensitivity and it's still too slow for me (In shooters I play at the max setting... Even Call of Duty and Bad Company 2). It sounds like your main problem is poor reflexes. No offense intended.
2. There is still no auto-aim whatsoever. Call of Duty and Halo are two of the most popular and successful shooters out there mainly for their mechanics. And guess what both liberally use on console versions? Auto aim. Implement it to some degree, and VATS will finally become an option.
I'd say the commercial success of those shooters relies on the multiplayer aspect of the games and the variety of game modes they can be played on. Comparing Fallout to Halo just doesn't work in that sense. Besides, V.A.T.S. is the most user friendly auto aim system there is... You hit a button and the game does pretty much all the work for you.
Auto aim is just a crutch for players especially in fast paced shooters like Call of Duty and Halo. Fallout isn't a fast paced shooter though. Players are rewarded for thinking through what they're trying to accomplish and exploiting their enemies weaknesses instead of just spraying bullets everywhere and hoping you hit something.