While it's canon and we can't really do much to refute it, it's still a pretty dumb contrivance that Saber's Servant level stats are all dependent entirely on Prana Burst when other Servants from her era WITHOUT IT have high tier attributes.
I mean, yes, it'd kind of make sense if she only had lower Servants stats without taking into account Prana Burst, but I don't think there is any good reason at all for her to only be as physically strong as a modern human teenager, especially taking into account that she did train to be a Knight and all that shazz.
Far as I'm concerned it's one of those iffy Nasu things we have no choice but to shake our heads with a sigh and accept.