PS3 player here. I have downed Twintania and I play a melee DPS job (DRG) and one other person in my raid group (BLM) is also a PS3 player. For weeks and weeks divebombs were hit-or-miss. If you're on PS3 and you're having issues with divebombs, it ain't PSN. It ain't your ISP. It's that stock HDD. Get a SSD and, trust me, your whole FFXIV life will improve.

The only role I really think PS3 would be a huge crutch to on T5 is healing. Short of that, though, get an SSD and be well.