First of all, I never thought season 1 Nash was as good as some people claimed. While Infiltration was very successful last year, he struggled after winning Evolution because players had obtained a far better understanding of Nash's offensive and defensive game plan. If my memory serves me correctly on all the major season 1 to season 2 changes, overall input delay was reduced from eight to six frames, which used to favor Nash's dashing game. Speaking of dashes, forward dash is slightly slower on start up. Back dash covers less distance. V-Reversal covers slightly less distance. V-Trigger was slightly slowed down. Moonsault slashes were slightly slowed down. MK scythe went from -8 to -10 on block. Forward and back throw leave the opponent farther away limiting guaranteed follow ups. Judgement Saber does slightly less damage. Nash did gain a couple of buffs but nothing to compensate for the losses.
I will let Capcom worry about the buffs. The "Nash is meant to be an offensive character while Guile is meant to be a defensive character" gameplay design makes no sense to me when Guile has superior offensive options than Nash does. Guile has better throw loops, an upside down kick that punishes throw attempts, and a V-Trigger that can be utilized offensively as well as defensively. Guile also has access to a fast fully invincible EX attack.