My opinion is expressed in this thread http://community.tacticsoft.net/t/what-the-new-patch-notes-would-look-like-it-tacticsoft-didnt-hate-us/4164 is there should be no inventory limit and it should be stackable. Theres no justification for saying that theres is not enough space in the supermechs world to fit guns, the game is about giant robots and guns. Just have the power of guns put into "fusion cores" so that your 17 saurus rifles are the same item, and the only data variable is the number after them.. for instance "saurus rifle icon, with the details on mouseover and click" x 17
Tie the powerlevels / upgrades / colouring to the slot in the mech that the gun goes into.
Equip the fusion core to a slot, it stays in the slot until you move it so you can swap out guns and the core stays in its slot.. If you have a level 16 fusion core, whatever gun you put in there stats out as level 16. You power up cores how you would power up guns normally, and you can sacrifice them to each other. You could even have the fusion cores tied to particular slots, drone / specials slots only for instance. you could limit the number of fusion cores to X+10, where X is the number of slots on 6 mechs.
As for obsoleting current myths, im not happy about it. I think that the old mythicals should be on par with the new mythicals, people spent a long time or money to get their current gear. It's cruel/stupid/unecessary to force people to destroy the stuff they worked so hard to get, and whats more I really dont agree with the way the current myths are handled, and I think its going to piss a lot of people off.
When you hear the Dev talking about strategy where he described this one time when someone used push weapons to push people into their long range big hitting gun, you know that the guys doing balance/design have the imagination of a potato. This also gives me cause for concern.
Lets face it, they are making all our stuff useless, honour would dictate that they give us premium currency for every mythical destroyed equivalent in terms of the new games economy equal to 80 tokens per myth. Every old myth destroyed should be equal to the value of roughly what it would take to get 50% of a new myth.