First one. I have the Arced War Axe, and the Sword from Crucible of Carnage. Today, in Deadmines, The Rockslicer Dropped. Should I use the Rockslicer, or is the Str sword still better? I don't wanna use it if the only thing that is higher, is the ILvl.
Second - I have the Helm from JP, but today once again in Deadmines, the Helm dropped. Would this helm be an upgrade over the JP version as it has a Blue Socket (With +30 str) Which will let me use the Meta that increases my attack speed. Should I change to this helm, or stick with my old one?
I'm not familiar with all the new (blue) stuff that may drop. Especially not since I play with a german game so names are again different. I don't want to look everything up for you so my answer would be general at best. My bigest concern with your post is, that I just don't know what you are playing. Reading on tankspot I would assume that you play a tank but than you speak about strength in a blue socket and haste meta. I assume that you wear plate because you seem to speak about a melee but don't want to have agi...
Item level alone is not much worth. If your are a plate wearing melee agi does not do much for you so stick with a strength version. That's at least for everything that is not a weapon. If it's a weapon the weapon damage is important, too. But I doubt that it will make all the difference for the big chunk of AP that you will miss.
If you want to get a better answer, you have to give more information in your question. Sorry.
dont go with rockslicer as both the arced war axe and obliterator are better than it for fury or arms (guessing fury since u named 3 2h weapons for the comparison) and the helmet is a little tougher. basically, if im thinking of the right helmets, it will come down to your rage gen. if your finding yourself rage starved constantly use the one from deadmines, if you think your rage gen is in a good spot at the moment stick with the JP one. thats the best i can do for you without an armory link and item links for the items.
I think I'd have to be drop dead impressed with a certain piece to pass up something a tier above it (ilvl 333 vs 346). So Rockslicer and Arced War Axe would be my picks. That's my rule of thumb and it's easier now with reforging and so far it looks like #gem slots seem tied to ilvl not random design (but I haven't picked up too many heroic pieces to confirm).
I don't know about the helm though, because I'm not sure how good mastery is for Fury. For Arms, if it were me I'd stick with the JP piece, but you're Fury...