Not initially but if you also invest one toughness advancement and a servo harness which isn't unusual or particularly hard for a leader imo he is then T6 3W and dramatically more survivable than starting there.Is T4 W3 with Scar Tissue (all incoming hits -1Damage) really more survivable than T6 W3 or T5 W4?
I'm always tempted by Natborn as it gives you a 2xp discount to getting S/T advance and choosing which. So you are only 12xp away from T8 which is just so nice/scary.
Unfortunately the goliath toughness shenanigans are over, one of the changes with the release of Ash wastes was to introduce minimum and maximum charectaristic lines, no fighter can push their toughness beyond 6 anymore (gear can still push beyond this but the maximum is now 7 with harness base). It was also 14 xp for taking the same advancement again, you forgot the 2xp tax for repeat stats