The biggest thing why seasons are just not worth it to begin with is that very, very few people play for an entire in-game year.
To make seasons a meaningful change for all gamers, you'd probably need cycles of 1 year per 50-80 hours in real life. That can only be achieved by either wicked short day-night cycles or omission of the majority of days in the calendar (with accompanying lore butchering or lore gap).
Not going to happen.
Though a storyline where some god is stealing time, resulting in missing days, would be an intriguing one.
You make a good point. But I really want seasons, real ones. It would be something very unique, compared to other games.
I guess the best way to accomplish this (if the engine can make REAL seasons at all, of course... which we hope for) is to shorten the number of days for each month. Instead of 30, go like 15. That's not too bad, I think. And the seasons last themselves several months.
I think 15 days per month is a good compromise. I think a lot of people would care much much more about having real seasons, than they would having a few more numbers in the calender, which doesn't really matter anything if seasons don't exist.
That way, if we go by Oblivion's timescale, a year in Skyrim would take roughly 144 hours. Now if we increase the timescale a bit as well (but not too much... that would be really weird and a break in immersion), we could possibly reach a year in 115-125 hours. Most people play that much I think, at least. Many people play a lot more... like 300 hours (this TOTALLY depends on how big the game is and how much there is to do!), at least in the previous games.