I mean, regular Saber with Rin as the master retains her agility, OG instinct and gets better mana supply, while also getting support from Rin. Not that far fetched to think she can beat this SAlter.
As for Herk, if Saber with Shirou as her master could beat him once in UBW, then with Rin? Yeah.
- - - Updated - - -
The Sasaki fight was less about beams and the spectacle whatnot (since she couldn't risk going all in that particular strat) and more so on swordsmanship. I thought it was pretty cool but yeah, its a shame that scenario with Saber never went anywhere (sans the Good Ending)
Then again, that's the fault of how the routes had been structured. You need all of them together in order to get the full picture, and each one individually is a fragment that answers and addresses the others.