Ethelina, we go fairly often (every year or so) but for very short trips. We did 3 day length-of-stay passes last year, and one year we did 2 day passes. This year we're only getting one park day, and one day of touring resorts/swimming/shopping at Downtown Disney. Yes, 2 days is WAY too short to see everything, but if that's all the time and/or money you have, you take what you can get!
When we did 4 parks in 2 days I had each child pick their 3 most important rides or attractions, and their one most important character. I guaranteed that they'd be able to ride their favorite ride at least twice, and their 3 most favorite at least once, unless the ride was broken down or something. I also promised that we'd do whatever we could (within reason) to find their one most important character. We were able to do all of their highest priority things, plus lots more. It was a very exhausting two days, but everyone left happy.
If you haven't been before, I'd recommend getting Birnbaum's official guide, since it has pictures and fairly concise descriptions of the rides and attractions. Go through it and decide what your priorities will be, what you'll definitely skip, and what you'll do if you have time. If I was doing 2 days this trip, we'd go to MK for a morning and afternoon, and EPCOT that evening to ride Spaceship Earth and Test Track, and see Tapestry of Dreams and Illuminations. The next day I'd go to AK just to do the Safari and Kali River Rapids, and maybe see the Tarzan and/or Lion King show. Then I'd spend the rest of the day at MGM, until Fantasmic that night.