Give Tyrion something far more interesting to do then what's in the books
They're doing a pretty poor job so far.
Everyone was so glad Tyrion's journey in ADWD was getting truncated... Cut out the fat, they said. Get to the good part, they said.
I guess Tyrion meeting Dany was cool, but now he's stuck doing fuck-all in Meereen. Compare that to what's going on at the end of ADWD and TWOW preview chapters.
He's smack-dab in the middle of an all-out war between slavers, Meereen and Greyjoys with two dragons wrecking shit in the sky. His involvement could dramatically change the outcome of this war, as he's conspiring to make certain groups change sides.