- It is true that Kreia's remarkable ability to drain the Force from the Jedi Masters and leave them devoid of it, and also kill them, has not really been identified. But I still didn't see her use on Scion or the Exile, when she knew that both were looking to kill her. I suppose there is a reason behind it, but I'm not aware of it. A remarkable feat truly. The ability to kill powerful Jedi with a mere wave of the hand. Kreia does indeed deserve credit.
- I would assume that Luke - during the Dark Empire days - was similar to Anakin. If Luke or Anakin ever reached their potential, they would probably be far beyond Kreia, Revan, or Sidious. Potential counts for a lot. Anakin was credited with a great deal more power than he actually displayed in Revenge of the Sith. Anakin and Luke seem to be stronger in the Force than Sidious or Kreia - so I would assume that is where Sidious's defeat in Dark Empire can be attributed to. Both Leia and Luke have the potential to become extremely powerful - with Luke already there. I presume it does indeed have to do with Force Connection - which we can assume - that Luke's and Leia's are beyond Kreia's.
- Luke, seemingly incorruptable, did indeed fall to the Dark Side. Sidious has a knack for manipulating extremely talented and powerful people into falling under his service and to that of the Dark Side. A talent that Kreia lacks - but then again - not something that is particularly useful in the situation. However, Luke turned for a reason. Not because he was tempted by the power, but because he knew he couldn't defeat Sidious. According to Star Wars.com databank, Sidious was virtually immortal - I would assume - due to his cloning. Or perhaps it is evidence of his high level of power.
- The Force Storm in the KOTOR games - even when wielded by Revan - is much, much, much weaker than that of Sidious. Of course, that is because it would sort of be unfair to have access to a feat that can consume ships and fleets. The Force Storm ability IS very great. I don't recall - then again I might lack the knowledge - of any other feat which can consume entire fleets.
- Sidious was also, apparently limited by his old age in Revenge of the Sith, similar to Yoda. In his clone, his mastery of the Force is equal to when he was old - except with the addition of a few new Force powers. He was in prime physical condition. He would be, in essence, stronger and faster than Kreia in lightsaber combat - considering she is an old woman.
And whatever Yoda's abilities are does NOT reflect those of Kriea.