As per topic, I intend to use him mainly in war and raiding.
I think the best way to emblem Gravemaker is to use barbarian emblems, right?
But if you are referring to the talent path, there is no best or worst path. Really. It depends on your play style and roster of heroes accompanying GM. If you want him to deal higher damage and DoT, then prioritize the sword nodes. If you want him to be beefier, then you need to look for the shield nodes. And if you want him to have high health, then the health nodes are the ones you need to activate. Heck, you may also choose to have a hybrid by a balanced combo of sword, shield and health nodes until he gets the +20. Again, there is no wrong path there as it basically depends on your play style and heroes accompanying your Gravey.
This is one of the heroes you can’t go wrong with either way. I personally went the sword path, that’s 342 burn damage on max. My take on that was that with very fast speed, prioritizing survivability is not as needed as for slow heroes (which you want to stand long enough to fire). I also don’t use him for a tank.
But if someone wanted to convince me into shield/hp path, I wouldn’t argue much. His DoT and direct damage are not greatly impacted by these few extra points in attack. And as many people plan to use him on defense, the longer he stands to protect the wing the better.
So I’d just say… enjoy the route which you feel makes more sense in your case.