Like I said I'm combining power with skill when assessing this as the question was 'superior telepath'. I didn't disagree that Rachel and KO have more raw power, the post you're quoting states that.
But we've seen her best Rachel with the explanation given being 'skill' + she's held off the PF itself longer than Quentin, making a better recovery, suggesting it's down to her skill. If we're talking superior telepaths as a category, raw power can't be the only reasoning. A great singer isn't assessed just by the size of their range, but their timbre and what they can do with their voice. By that metric Jean probably still outranks Emma, in the way Rachel would if she had Jean's skill and imagination to back up her raw power.