Eh, you think so? I already realized that with everyone getting plus 2 from Killer weapons, toughness is either all or nothing. People don't wound T1 any better when their Str is 3, or if it's 5 or 6. Having +3 Str -1 Toughness, would actually make her MORE likely to lose to Setsuka. Vs a "Normal" player with T3, there is also no difference between Str 5 or 6.

And, any PC fight, save between two heavies or people who take the +2 toughness killer weapons, is statistically likely to be over within two rounds, so you might as well have your killer weapon on right from the start.