Absolutely NO 3rd person.
GOD... it would make piloting your mech a damn nightmare anways... WHY would you do that (excluding console tards were everything has 3rd person - they just dont get it). Can you imagine how far the camera would have to be pulled out so can fit an ATLAS onscreen WITH enough view to actally perform combat? It would be miniture - would turn MWO into a semi RTS you would have to pull soo far out...
AND if you go 3rd person over the shoulder, then your entire side of your screen is blocked by battlemech *** leaving you completely blind that side.
ONLY reason 3rd person is actally INGAME is because:
a) Dying in cockpit would be odd without it... unless you totally dig a sudden flash and then a black screen before being able to spectate.
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THOUGH I WOULD TOTALLY DIG BOTH.
I would LOVE to stay in cockpit when i trip!