I just read a very long interview with Ron C. (headwriter) ....who talked mostly about this time jump (and he hates spoilers, so there is not even one in the interview, which is several pages long) and how long he has had the idea. Pitched it to the other 2 soaps he worked at, no go there. But when he talked about it to Days, they were intrigued. Originally he was going to do it when Marlena was in her coma, but there were a couple of glitches that made that not feasible.
The thing is, as a writer, you have to know what every single character has done for the year, where they are at the jump, it all has to be in place. Originally he thought with the 2 pregnancies, New Year's would be a good time, clock striking 12, and an entire year has passed. But Ryan Quan came up with the "anniversary" (Days, which was Nov. 8th) which worked out perfect. They wanted a legacy character to be learning everything, along with the viewers, so decided on Jack & Jennifer, who had just had all their happiness back...and bingo.
He also said, thus........some couples are together, some not, few people have died. He said we would slowly learn all that occurred, and there was one thing it was going to take longer to find out. He also mentioned how he had not taken production into account.....mentioning they do 8 shows a week (& we wonder why they are so far ahead), but, when doing flashbacks, there has to be change of hair, clothes, sets, etc. & the production crew has done a fantastic job. He said the cast is very excited by all this, & he hasn't heard anyone saying they were unhappy with whatever their character was doing. He absolutely hates spoilers, feels everyone should be surprised, wanting to see what happens tomorrow. Thus was really glad this time jump was not leaked long ago. He hated when it finally did a month or so ago. LOL