I remember a very similar topic have been made a couple years ago. I remember almost anyone agreed on a certain name, but can't really recall which one.

Kinda like Orbital Drop Troopers a lot better, honestly. Makes a bit more sense being as we have our own Warbarges and at some point -MUST- break orbit in order to get planetside. Course, that being said, sort of similar to Orbital Drop Shock Troopers (ODST's or 'Helljumpers' from Halo).

Orbit Breakers. Maybe. I dunno. Sort of spitballing atm.

Nephilim

I could easily see some political "puppet master" types sitting in a dim room, talking about some planetary operations, the assets they have in orbit and on the ground....

One of them strokes his beard and asks: "What is the situation with our ODTs?" (ODT = initialism for Orbital Drop Troop)
A woman, standing by a window looking down at the planet replies: "We have a contingent on standby."
The bearded man motions to technician sitting at a terminal and says: "Send them in."
The technican replies: "ODTs en rounte. ETA: 5 minutes...."

Initialisms make sense. They generally sound good and official, and are quick to use. There's a reason why militaries use them. Saying mouthfuls like: dust bunnies, Wayward Soldiers, Apostate, etc? Well...

The term capsuleer is, as far as im aware, an original term. Perhaps a hybrid of pioneer and capsule, one who pioneers through the universe in a capsule, or some other suggestive meaning. But the word, at least, is original. What you suggested is not only not original, but fairly over used in the gaming industry in the last five years. Kinda cliche, even, and it instantly recalls memories of Diablo 3's hilariously bad storyline as well as the DMC reboot, and the dragon age series with its fall from grace. I would think we should avoid that, and instead look toward the creation of a new word entirely.

you're welcome.

Also: Dust bunnies. period.

As Longstrike-haani mentioned previously, there's an old Minmatar folk legend of warrior spirits called draugr or 'again-walkers.' Though the term is mostly applied to immortal mercenaries in a negative context by only the most superstitious civilians, I've found that baring the title as a badge of pride tends to yield results within the Republic. By that I mean, people will take you far more seriously and be less likely to argue with you when you are trying to peddle a mangled flux coil to a Sanmatar.

Elysians in Gallente populations is also a common term, but you have to bare in mind that in the Federation people look to our kind more as sports stars than professional soldiers. We're a source of entertainment, and some of the more... ehm... Outgoing mercenaries like that of the infamous Kirk have a rather large following. Templars seems equally prevalent in Amarr society for obvious reasons, though the APEX line of dropsuits seems to show a shift to the alternative term 'seraphs' to mark combatants not requisitioned directly by the Amarr military.

Lastly, there is Rasetsu within the State but this term seems exclusive to shock and assault troops. More often than not troops within different specialized units will have some sort of name for themselves from Raata demonology. Baku for air assault, kappa for amphibious landings, yurei for practically anything else... Frankly, the best term I suspect that we all agree on that translates well into different cultures is a type of noble soldier we call the samurai.

Has a nice ring to it in my opinion.