I now have mine completely in pieces and have had ALOT of time looking at it as I have disassembled it, and have looked at, USED, and have worked on many snow blowers over the years, the Cub Cadet QA-42A snow blower attachment that I have here and my Deere 828D walk behind (which is actually an Ariens built machine)
Looking at that baffle that you say to remove, I was all ready to cut the few spot welds that hold it in place, but didn't. The Cub is a single stage, so I don't know if that is a fair comparison. most other machines I see, the discharge chute is completely open, not half blocked off.
But in this case I do not see where taking that baffle out will benefit much if anything. The reason being, look at the length of that 2nd stage impeller. It is just the width of the portion of the chute that is open. If the impeller were longer, as in the length being the same as the diameter of the opening without the baffle, I could see it being a restriction. But since the remaining opening in the discharge is no skinnier than the impeller, I think it might hurt throwing distance and volume.
I would have to cut the housing itself to match the size of the chute opening along with that baffle.
but output wise I don't see how it would throw more, or throw farther, unless I were able to retrofit a thicker 2nd stage impeller wheel.