You don't like mods? Well I can understand that, they're not all of equal quality. But OJP Basic doesn't mess with the core gameplay or "look" and "feel" of the game. It just offers bug fixes and has a few options that make things run smoother. Unlike a great number of mods out there, it doesn't contain any "abusive admin commands" (that are often used by hosts of games to cheat or bully people out of the game and other immature behavior).
It's a small mod that's easy to use and the guy who created it is a reasonable person who listens to feedback. You've got nothing to lose by trying it.
The reason companies don't do more is because of profit and diminishing returns. Most game companies figure that 4 months to a year after a PC game comes out, everyone who wants to buy it is going to do so, so they drop support in favor of newer games. So unless it's a major, major game that has sold millions and continues to be played by as many, don't expect much after that from the developers.
The other complication with the JK series (after Mysteries of the Sith, the last "in-house" created installment in the series), is that it's a licensed property. So Raven can't release any "official" fixes without first going through LucasArts. So if LucasArts doesn't let them (and pay them, probably) to keep working on it, they have no incentive, and even some legal disincentive to keep working on it.
If they did anything it would be in the form of unofficial mods, like you and me, which they would release in their capacity as individual "fans" and players, rather than as LucasArts reps or Raven employees. But even then, professional people have limited free time to work on stuff like this, so you can understand if they don't anymore.
That said, most of the main bugs people complain about HAVE been fixed by various mods out there. Others can be worked around, but some are just inherent in the engine and could only be fixed by a major rewrite, which nobody is prepared to do, especially for free.