I'm aware of the method of the transformation, it just makes it even LESS impressive to me.
Had Betsy set out to make herself more of a fighter then I would have been fine with it. Brawn augmenting brain is hunky-dory. But she didn't, she put on body armour shortly after Doug was shot dead (A connection there? Perhaps) but other than that did very little to improve her physical combat skills.
And as I already noted, not winning against Sabretooth isn't a decent test of anyone's competence as a combatant as he's a better fighter and killer than over 99% of the population of planet Earth. She was more than capable of using her powers to flash-fry the mind of the twisted Captain Britain analog who tried to assault and rape her. Her telepathy makes her affective against just about anyone OTHER than an animalistic being like Sabretooth.
And as it turns out, her desire to become more of a fighter led to nothing from her own self. She didn't actually achieve anything, she became a fighter because Spiral waved a metaphorical magic wand and made her into one because it amused her to twist as aspiration that Betsy had. That always struck me as more contrived than interesting.