There's always in-universe explanation, one of them is explained by Jak.
I deconstruct it in ST, and reconstruct it in TLR Stratos, in that while she's good at everything, she's not the BEST in everything.
Think of an RPG character that have well-balanced stat, even if she has bonus being 'superbly talented' (+20 all stat, for example), there will be someone with higher stat in one or two aspect (Ichika and his martial arts, Houki in Kendo etc). In ST, this is used to justify her '
can't catch up' mindset.
Tatenashi's true strength is ability to gain higher ground by exploiting her target's weakness, and is the reason why she will become a leader figure in future chapter