Nah, it still matters where you hit them, it clearly leaves more damage at the area that is impacted (hence the spiral-shaped wounds). While it's obviously not nearly as pinpoint in its damage as Chidori, it still makes a difference if you aim for a lethal location or not. Naruto, Jiraiya, Minato, Konohamaru... all of them always go for a non-vital spot, every single time. That's just the way the attack works in the manga, but realistically if they hit someone in the face with a Rasengan it'd be a 1-hit kill. You can't just ignore the fact that Rasengan always hits someone in the gut and sends them flying, purely because that's how Kishi chooses to draw the attack/demonstrate the damage.
I don't even question it anymore, I just accept the fact that we'll always see the attack misused. It's like how Kenshin's final move was always a swipe across the torso, and never aimed at someone's face/neck (although he explicitly had no intentions of killing). It's just a big flashy move designed to send bad guy's flying, leave them KO'd but not dead, and leave some superficial injury to prove the bad guy got owned.
Anyway, the new chapter better be out in like 2 seconds, because if we're debating the lethality of Chidori/Rasengan in terms of piercing power/area of effect damage, and the nuances of all the Chidori/Rasengan variants... well, let's just say it's not the most interesting discussion we've had.