You can't pinpoint the most powerful jedi. You can pinpoint them in separate categories... but not in an overall fashion. Galen Marek had incredible strength... but not too much wisdom. Revan had a great leadership level, but was defeated by a few players in SWTOR and could not sense betrayal. Anakin was powerful in the force, but was overcome by confidence. You get it? All of them have weaknesses and it is nearly impossible to decide who is the greatest jedi.