Yeah. Even Takamina was a bit frustrated with the situation. They had a whole year to set up her graduation for the 10th anniversary. But hey, at least a bunch of original Team A, K and B members will be in their 10th anniversary theatre. ^^;
From what I hear from other sites, Takamina was initially to begin her solo activities after graduating on 12/8 and AKB48 was going to get a new start beginning the new year. They sorta plan on keeping it as her group activities will end by new years. Personally, if they release a new single prior to March 28, it'll be weird since Takamina is technically still in the group.
Edit: Tokyohive article
http://www.tokyohive.com/article/2015/1 ... n-march-28