Actually, I would say that the Sion battle would help her out.
Sion was pretty much an undying machine. He just kept getting up, so Meetra going three for three (was it three fights on Malachor?) against him on Malachor greatly benefits her. Sion was getting immense power from the planet's Dark energies. Meetra displayed excellent skill with the lightsaber and incredible stamina to fight Sion. Not only that, but she also used Dun Moch against him. Her use of Dun Moch eroded his will, the same will that had kept him alive for so long. Sion eventually confessed his love for Meetra and gave up the Dark Side.
Now we could argue about why she didn't use Sever Force to beat him. The answer is quite obvious. Sion lived off of the Dark Side. Severing his connection to the Force would kill him. Instead, Meetra practically redeemed him.
Granted. But if Meetra was male then she could not have won the fight 'cause Sion would have eventually worn her (him I guess) down. See what I'm saying? Put any other Jedi in her shoes (Like Obi-wan why not?) and that person wouldn't have been able to beat Sion. Does this mean that Meetra is more powerful then Obi-wan? No.
Correction: I suppose she could have used severe force like you say.
But regardless, you see my point.