I'm inclined to agree. I think Malak did eventually surpass Darth Revan in power, but I think he took the same route Sidious did by minimizing the risk and striking Revan at the right moment.
I think he did surpass Revan in power. On the Star Forge he was counting on the Star Forge's droid factory defenses to be able to destroy Revan. After seeing that Revan was able to get past them he realized that Revan had become far more powerful than he ever was as the Dark Lord.
Overall, I think had Malak just waited for his opportunity to defeat Revan instead of firing on the bridge of his flagship, then he would have succeeded in destroying Revan and conquering the galaxy. At least until Emperor Vitiate finds out that Malak had succeeded in being his vanguard to destroying the Republic.
The final result would be that since Malak didnt leave any key infrastructure intact to be able to defend his Empire, Vitiate's empire would just step in and conquer Malak's empire with relative ease.