First of all, PvP in this game isn't that good anyways so don't complain. Second, they did nerf the Mytho once, so hard that it was doing bad in PvE. So they had to give it a buff. You're also lucky they didn't keep Field Scout on the Mytho and gave it the weaker magazine boost, because it originally held up to 56 rounds in a mag with FS. Also just wait till the IB comes back when everyone has their Suros Regime upgraded thanks to XUR. Then come back and complain.