the Rof buff was for the main gun. It's now more vulnerable to handheld AT and therefore less effective against infantry.
It only lost its vet2 armour buff. It's normal armour is still the same and it is more than enough against handheld weapons. With better gun it actually has a chance to reach its veterancy now, even if the modifier list doesn't mention armour buffs. Still, you are not and were never supposed to fight AT infantry with panthers, although it can kill AI infantry quite quickly.
The changes that were applied to panther are actually a huge buff. One of the most important ones, that is often forgotten, is lowering the spread of reload times from 0.9 to 0.4, which means it is finally easy to use stop micro with panther, as you don't have to guess the moment it will shoot. That 0.5 of second is enough to let you shoot on the move with all benefits of standing unit, without having to gain all your speed again after the shot.