I don't think any specific conclusions have been made about the Wrath of Khan date, but the thing that irks me about the 2285 date is the "fifteen year" reference to Space Seed that both Kirk and Khan make, independently of one another. That both of them would give the same date, with Khan being smart enough to do the math in his head and Kirk not having particularly thought about it in over a decade, seems to indicate that it's pretty on the mark, with wiggle room of no more than a year. (To account for it maybe being closer to 15 and some months or 14 and some months.) Whether that means Space Seed needs to be moved up or Khan moved back, I don't know. It's probably both depending on how you want to interpret the 2283 reference.
IIRC, the problem was Generations, wasn't it? Some reference to Kirk's time away with Antonia (nine years before 2293?) led the Okudas to fiddle around with the film timeline, forgetting or ignoring the Khan dates. I don't have the first edition of the Chronology to check. So any attempt to move Khan back from the 2285 date would need to square with that as well. (I think it can be done; I just don't remember the relevant info.)
YMMV (especially on nitpicky things like this) but keeping the episodes in production order provides consistency on some minor issues, such as cosmetic changes to the sets and things like uniform colors and rank usage becoming more consistent as the seasons go on.
That said, I definitely agree that there's no need to assume that each season covers a year of time, even for the later shows. I know the writers and the Okudas generally assume that it does, and I'm sure that's more or less accurate on average. But I'd rather get a more accurate sense of time passing during specific years by noting the references to days and weeks, etc., in the episodes themselves. Maybe TOS season 1 can't take place in less than a year and a half, Enterprise time, while all of the animated series could take place in as little as five months, for example.
TC