Well, I'll do my best:
Lou Mongello's [Probable] Answer
Limited Time Magic brings you and your family new, unexpected magic each week of the year promising your group something new and exciting whether it be on a large scale like Cinderella Castle or something subtle yet very magical that will surely help create memories that you'll savor forever. Now, a visit to one of Disney's world-famous theme parks can be even more magical as if it were not magical enough!
My Version
Limited Time Meh is basically just a promotion to entice people to visit by offering a series of last-minute, poorly planned opportunities to spend money throughout the year. Occasionally, they'll do something somewhat big but usually those things are announced much earlier. Generally, LTM isn't something you'll know about until the Friday before your arrival date.