F6F-5 doesn't really over that much over the F6F-3 in terms of Air to Air performance, they added water injection and the roll rate is improved somewhat but I'm not sure if it was the degrees per second that was increased or the stick forces required to deflect. (not sure how much of an improvement it made, I'll have to check when I get home)
While important I don't think it would through things off too much. The F6F-3 was already faster than the opponents it faced, and even with the spring tabs I the roll rate isn't the best out there.
More concerning, and I consider the strongest argument for using the F4U-1 instead of the F6F-5 is the ordanence capability of the -5 Hellcat.