I would say the advantage of using leather armor instead of chain on Warrior rogue is that you can use the same set of gear for Rogue Warrior. If you went with chain wouldn't be the case.
Also most leather pieces Plus for strength and stamina. And most chain pieces Plus for dexterity actually.
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This is not at all true. Chain gear has the same amount of crit as leather gear while having FAR FAR MORE physical attack. If you're only interested in playing a chain class, chain gear is far superior to leather.
As for armor, wear the leather as statting one set of armor is far easier than statting two. The armor bonus whether chain or leather is kinda moot as it gets overshadowed by the stats you put on it. The one important thing not talked about above is that Leather gives you more crit whilst Chain gives more physical attack and it is far easier to add physical attack stats than to add crit.
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There is actually a rogue/warrior elite skill that gives the 70% buff for axes on the rogue. I use axes on both classes. You lose a little speed, but the dps is still better.You are going to want to use daggers on the rogue and axes on the warrior. One fast statted dagger in your off hand used on both while swapping between a tiered dagger and a tiered axe depending on your main class you are playing at the time