Jobs can already share gear. All healers share gear, all tanks share gear, all ranged physical dps share gear, all ranged magical dps share gear, MNK/SAM share gear and DRG/RPR share gear. Even NIN shares right side with ranged physical. The only thing they don't share is their weapon.

It's not like it's hard to gear a second job. Just go to the market board and buy the latest crafted gear and it's actually overpowered for most content already and good enough for savage.