The people who created the game thought in very narrow and binary forms. They were not capable of handling the concepts of a wider narrative. It is all over the game.
Think of the ridiculous alignment system. No well-acted character who has enough to do it going to adhere to one of those alignments in absolutely every single aspect of their life.
Lawful? Generally speaking people obey the laws that carry a weighty punishment and/or they generally agree with. But probably everyone breaks minor regulations every now and again. And if you put someone under enough stress, enough danger-- hell, just get them drunk and it is more likely they are going to break more laws.
And Chaotic? Unless someone has truly ascribed to some far flung philosophy, someone's level of chaoticism is going to be directly drawn from how high of a position they have in the society, how much the laws generally favor them being them or, conversely, seem directed at oppressing and eradicating them and even then they are likely going to have a chaotic philosophy in some aspects of life and a nonchaotic philosophy in others.
Same goes with good and evil. People naturally sway from one to the other all depending on their opportunity to do harm and the amount of benefit they would draw from it. Reward anyone enough and they are likely to commit an evil act. Particularly against a stranger who they have never seen before who speaks another language and especially if it is a person who is part of the group the person has labeled an "enemy".
But they said instead.... no. You must pick a single philosophy that your character is defined by 100% of the time in all their words and actions and any straying from that for any moment deserves a serious experience point penalty. No, no. It gets worse than that. You embezzle money from your job? You agreed to work for the thieves guild because they were the only one who would hire you? Well, the Detect Evil spell says you are the same thing as a demon and therefore have forfeit your life. Of course, there were a lot of classes that had very specifically proscribed alignments that they were incapable of ever changing or altering.
Combine this binary morality concept with the most miserably thought-out races one could possibly imagine.
Most races were incapable of taking any class but Fighter and probably Thief. In fact, basic had Race-as-Class which just meant that if you were a Dwarf or Halfling then you were a Fighter and if you were an Elf then you were a Fighter/Mage.
Yes, what this means is that while you might think it was the model company that decided races should be manufactured lines of identical clones, in fact from moment of conception of the idea of non-human races, they were all nothing but clones rolled off an assembly line. Each of them with exactly the same background, exactly the same personality traits, exactly the same characteristics, exactly the same strengths and weaknesses, exactly the same skills and abilities... no difference at all. Hell, two Pokemon of the same kind probably have more difference between them than 2 1st edition Halflings. Okay, your ability scores could be fiddled with a bit-- but unless they were belong 9 (in which case you might not even qualify for the race) or above 14, it made no difference. And since every member had the same abilities and skills, your ideal ability scores were set in stone. So all that really mattered was... well... what level your Dwarf clone was and what name you decided to give him.
So given that there was a binary alignment system and the fact that races were clone armies, it should come as no surprise that nonhuman alignments were set.
If they were friends of humans, they were good. Regardless. REGARDLESS.
Dwarfs can be not only racist, but genocidal, maniacal, mouth-foaming, blood-thirsty, grudge-bearing, vengeance-seeking, insatiably greedy bastards whose sins are so great that they think nothing of destroying all of civilization to kill the last goblin and claim the last gemstone.... yet, somehow, they are "good". Yeah, the guy who wants to kill you and all your kin for your grandfather cheating his father in poker 80 years ago is "good". The guy who is going to knowingly release the fiendish invasion to dig some more gold ore out of the ground is "good".
Elfs and Halflings are also universally considered good.
Oh, there are non-good Dwarfs and Elfs, but they have black/purple/gray skin and live deep underground. The Caucasian-looking ones were universally good.
And bestial races? The ones that are bigger and uglier than humans? Well, they were even more sets of indistinguishable identical clones than Elfs and Dwarfs. For they only level up if enough of them gather in one place for one of them to qualify to get another hit die. The idea that any Orc could be different in any way from any other Orc was just simply an incomprehensible idea to those who designed the game. At least at the time they made it. There could be an Orc who would align with humans? A whole tribe?.... Nah. The only way they could be playable would be to make them half-human. And so that is how it was and has always been since.
In fact, just to completely nail this simple idea down...
The first time TSR put out a book that allows you to play Orcs (and Goblins, Kobolds, Hobgoblins or Ogre), it stated right flat out within the first paragraph of the section telling you how to make one "No one could take playing an Orc seriously".
That was their mentality. And it wasn't until 4E that rules reflected anything different.
Before the 5e MM I was thinking about making up an alternate story for Half-Orcs in our games, dropping the stale and awful standard of their origin, and instead going with the idea that Half-Orcs are not individually 50% orc and 50% human, but rather only as a whole, i.e. an intermediate race between orcs and humans that doesn't breed with either. This would allow me to have Half-Orcs feel the role of the popular WoW Orcs, to which they also have a much stronger physical resemblance compared to 3e Orcs.
So your "creative" and "good" solution is to... rip off 4E.
You know why don't you just take that one last step to 13th Age's stupidity of them being a race utterly and completely distinct from Orcs, never interbred and the one thing they have to do with Orcs is that they were created by the Great Druid primarily for the purpose of fighting Orcs... but they... are called "Half-Orcs"... because..... "duuuuuuuuuuuuuuuuuuuuh".
No, seriously-- why the hell do they need to have human blood at all? What is this mentality that they need to be half-human to be heroes? No such requirement is placed on Halflings. Should we make Elves unplayable and say we will use Half-Elves instead?
If Elves are diverse enough to have High Elves and Dark Elves and Wood Elves... I certainly do not see why one cannot have a subrace of Orcs that retained or regained a bit more intelligence than most at the cost of some of its brutality and animal instinct. After all, Orcs appear by all measures to be smaller cousins of Giants... and Hill Giants and Cloud Giants are not of the same intellect level.