OP- cutting that out will do nothing for improving discharge IMO. The deck wold probably be more than stout enough without it, but it is there for a reason, which is to add strength to the rear side of the chute opening when going over obstacles like tree roots etc. If you snag the lower rear corner of the opening, or if you have a rear gauge wheel there and it gets snagged in between roots etc, or takes an impact from some other source it is possible that you could cause damage or tweak the rear corner of the deck. If you watch your discharge, most of it comes out at the front of the opening anyway, so like I said, removing that will most likely not show any improvement whatsoever..
Here's my baffle. It was designed to sorta mimic the Scag Turbo baffle. It is there to prevent the clippings from being re-circulated around the right blade chamber. In some cases it does spread the clippings out better, and in others, it doesn't do much of anything. It is like blades.....you have to pick the right one for the conditions, and so it is with the turbo baffle.