Okay, last time Kreia saw Revan was a long time ago.
Most of his new skills were not seen by her because he found them out during the Jedi Civil War, Kreia had no idea what Revan was doing then. She wasn't around, if she was then it was clear that Revan was the master then and even Malak was more powerful then her. Since I doubt that she just wasn't around. Meaning Revan learned a lot when she wasn't around.
Kreia also wasn't around during the Mandelorian wars, or at least not all the time. She is not an important general and did not have a very important place at least not important enough to be mentioned and known around the galaxy. Even then she was below Revan probably with a reason.
The things Kreia had acces to were very limited compared to what Revan had, especially if you consider that Revan was there first, he was on Malachor first, he was on Korriban first, he had the star forge and the rakatan home world. He also controlled the Star Forge which takes a shit load of power.
And thats just somethings I can think of in a second without really thinking about this topic (I'm to tired to think clearly now) One more thing however, if Kotor 2 would have been finished, Kreia would have followed Revan his orders. There would have been a reason for that.