Once we know more about Shoha's attack bonus then we can factor in the whole /WAR vs /DRG debate. The entire point of /DRG @75 was that SAM's best WS (Gekko at the time) would cap attack with berserk and thus the potential of /WAR was mitigated. /DRG allowed more haste for your 6-hit.

After Fudo was made and it became much easier to cap haste, /WAR came back into style due to berserk and DA.

Now with Shoha, being pretty much the best SAM WS, having an attack bonus, it might make the berserk of /WAR invalid again. So your looking at various x-hit builds and haste setups.

If we talking hitting a brick wall with infinite HP, then the 4 hit should trash the 5 hit (assuming berserk does nothing for shoha, that's a REALLY big if). x-hit means that many hits from 0, most of the time you'll have a full swing in so it becomes Ws + 3 vs Ws +4, or a 25% increase in WS's. This doesn't take into account the extra hits from jumps nor the delay from activating JA / WS. If I had to ballpark I'd say in the 10~17% range difference.