I was thinking about something earlier…are SPARTAN-IV’s even worthy of the title of “SPARTAN”? Their training, upbringing, attitude and abilities are so far detached from what made SPARTAN-IIs and IIIs actual SPARTANS it seems almost silly to group them together.
At best, they would seem to be just really suped-up ODSTs (and what happened to the ODSTs anyway?). In fact, the only thing that seems to make them even close to SPARTANs is their MJOLNIR armor, but being a SPARTAN is so much more than just the armor - after all, SPARTANs were SPARTANS long before MJOLNIR existed.
They have vastly inferior training - SPARTANS have a lifetime of dedicated training and effort put into becoming SPARTANS. SPARTAN-IVs are just regular Army and Marines that decided they wanted to try out and be SPARTANS. Their training is also ridiculously short - under 6 months of training total (remember, Thorne says he was Regular UNSC Army when New Phoenix occurred, and then decided to start with the SPARTANS), possibly even shorter than what we know of for ODST training.
They’re biologically and physically inferior. SPARTANS had many specialized operations and treatments to push them past recognized human abilities as well as being specifically selected for superior genetics, and that were largely responsible for their super-human capabilities. SPARTAN-IVs are largely unmodified.
They’re poorly disciplined - as Thorne, Palmer and Majestic Squad’s Token Black Guy like to illustrate. A nuclear strike couldn’t cause real SPARTAN’s to break.
They’ve got attitude problems. Someone with Commander Palmer’s attitude would’ve been broken (physically and mentally) during real SPARTAN training until she was no longer an abrasive -Yoink!- and could actually treat people with respect and keep a cool head; not to mention the other issues they seem to have.
So basically…they lack everything that made SPARTANS SPARTANS. Calling SPARTAN-IVs SPARTANS is like calling a RA Nurse a “Medical Doctor”. Same “field”…but no where near the same thing.