Well, they added the adjustable eyepiece. Six of one, half a dozen of the other.
Since I still have good eyesight, I don't need the built-in diopter adjustment and much prefer the huge HD viewfinders of the OM1&2 and Pentax MX/ME. But hey, almost 30 years later, none of this matters except enjoying them. Of course what's most important when picking up one of these classics is that they have that "PASSED" sticker . . .