You don't understand; the reference is obviously not "combat-related" power. It's not the strength of a Force user during a fight, otherwise Anakin Solo (the child) would have been a complete nonfactor during the fight - he wasn't even born, so his combat abilities would obviously be nonexistent.
It has been implied throughout the entire continuity (and makes complete sense) that Leia's strength in the Force equals that of her brother. Hence why Vader said in RotJ that he would use her if necessary. The obvious difference is: Luke is far more experienced and more trained than she is. But her raw strength in the Force is quite likely to be equal to Luke's own.
Anakin Solo's strength (from what we saw before his death) was extremely proficient as well, though I don't know if I'd put him on par with Luke or Leia in terms of raw Force talent.
There's nothing to indicate that Revan's strength in the Force comes close to Luke's own. And if it does, that means he just has 1/3 of the power necessary to strip Sidious from the Force and defeat him.
Revan doesn't have the raw power to tackle that.