What I'm seeing, is people saying the heels are a problem because of the underlying association that heels are an oppressive symbol of femininity as well as being impractical and unsuitable for the everyday and are only thrust upon women because human society says "you must wear these to make your rear look good".
This apparently conflicts with the perception of Samus as "empowered woman freed from the shackles of femininity". She's a badass bounty hunter. She commits genocide of an entire species and eradicates planets and takes on a fleet of space pirates single-handedly! HOW DARE THIS FEMALE WARRIOR... entertain any notions of Femininity?
"The heels serve no battle purpose! And would likely only hinder her abilities!"
Unless they don't?
What if I told you I had a pair of gloves that would help you do more damaging punches by causing explosions in peoples faces and adding greater force to your movement? ZSS is described, according to the wiki, as having Quote: "superhuman acrobatic skills from her Chozo DNA and training" and her DNA "gives her speed and agility beyond the capability of ordinary humans". I wasn't able to find a single instance where it says that Samus has super strength (although the above poster says she grew up in 900x normal gravity, not sure how game canon that is though. I'm no lore buff) See Edit Below. So maybe her kicks aren't that strong on their own...
Maybe the rockets in her heels aren't about speed, they're about creating a greater, more explosive impact (or at least fire damage). And what better way to deliver damaging force and firepower to a high-speed kick than with exploding heels? I'm pretty sure that her superhuman acrobatics makes the uncomfortable or awkward torment of walking or running in heels (for normal humans) childs play for her; its a non-issue. And if that's the case, if the heels actually HELP her physical combat capabilities, wouldn't she as a warrior go through any training or use any item necessary to increase her combat prowess? Including using heels?
I like the heels. They make her tush look good... and give her powerful kicks.
_____________________________________________________________________________________________________________________
EDIT: After looking at the data on Zebes on the Wiki - pulled from the Metroid Prime game - it does say it's mass is " '4.8 trillion teratons', or 4.8 trillion trillion tons" which would support the 960x gravity statement. HOWEVER, it goes on to say that this is likely a mistake as teratons....
Teraton
(noun) - A measure of the strength of an explosion or a bomb based on how many trillion tons of TNT would be needed to produce the same energy.
And suggests that for mass, the correct measurement would be kilograms. So really the correct measurement of its mass would be 4.974x10^24 kilograms, which is actually LESS mass than Earth (5.972 × 10^24 kg). Which makes sense, since the planet is described as having a hollow crust. Furthermore, this measurement of mass is supposedly backed up by the Japanese Official Nintendo Super Metroid Guide Book.
Therefore, the idea that Samus has super strength is likely a fallacy. She's just really fast. Hence the need for the suit; and the heels for added force to her kicks.