The East stage 3 is the most difficult by far.
Central is the easiest, and the West was on par with the stage 2 difficulty.
I’d switch East and west in your order personally, although I guess it depends what final boss you play. I think West has the harder moments but Marichal and Catfish are easier to face than Palmer/Leiter/Smoltz/Henke. If you get Hershiser the west is difficult
The reason the East is hardest for me is two-fold. First, the final bosses, especially Palmer are difficult for me to hit for some reason. Secondly, the moments leading up to the final showdown are typically offense and pitching goal oriented, making it that much more difficult.
The West is on par with stage 2 because I usually have 12-13 runs by the time I make it to the final boss.
And the Central is easiest because of the final bosses and many of the moments are strike out 1 batter, hold the 3 run lead, score a run in the top of the first etc.