You are partialy right. But you are partialy wrong too. Bastila isnt Vima sunrider shes an Original character all together. For once in KOTOR is very clear that her mother isnt force sensitve and was never a jedi. I mean i would certainly cry if the Nomi sunrider would pass her last days in a cantina in tatooine.
As for batle meditation, being a power that can ne naturaly gifted to some jedi, doesnt mean any jedi powerfull enough cant learn it.
That is only because Lucas could not acquire the rights to use the Sunrider name. Had they been able to use the name, those story elements would not have been changed to accommodate a new character.
In the end, however, Nomi was an expert with a lighsaber and a master of the Force. She had only been a Jedi for a short while when she severed Ulic Qel-Droma from the Force. There's no telling how powerful she became by the time she was appointed Jedi Grandmaster of the Order.