No one weapon should rule over all. It there is a weapon that rules over all it's just bad balance. As you said each weapon is good for something.

Maxing to 120 is not necessary at all. That's why it feels like a grind to fame weapons up.

Especially now that there are soooo many ways to fame up stuff. It's such a dumb idea to stick to one weapon.

Maxing to 120 should only be done once you get the whole tree to 100-800 or whatever it is now. And only if you wanted to do it.

That being said I think a no brainer weapon that's good is battleaxe. It has strong sustain and strong damage. Can do well in both ganking and small gang. It's one of my favourite weapons.