So let us do some actual comparison work:
TIE Defender: 6 hull, 5 speed, 2.5 average damage vs squads, 44% chance of 1 accuracy, .75 average damage vs ships
E Wing: 5 hull, 4 speed, 2 average damage vs squads / 1.5 with snipe, 68% chance of accuracy / 58% with snipe, .75 damage vs ships
So on that basis, the TIE Defender is slightly better unless you can leverage snipe, at which point the selective engagement matters for the E-wing.
Thus, question one: does snipe matter to you?
The other fly in the ointment is that while Imperials have one dominant all-around choice (TIE defender), Rebels also have the A-wing (maybe the best all-around squadron for the points in the game) and the YT-2400 (which allows more combat ships). The imperials have no equivalent.
Side note: I think the phantom will see more play with Sloane. She is huge for the anti-ship capability of the Phantom, as accuracy now hurts and re-rolls of crits mean 1/4 of red faces cause a re-roll for the Phantom.