The halts of a Rajdhani are given based on patronage I think. In case of Howrah Rajdhani, most of the patronage is either end-to-end or from Dhanbad, Gaya or to/from Mughalsarai. So, no use of giving any more halts, as it will reduce the average speed (like August Kranti Rajdhani). There was a poll conducted where I voted "Yes" in favour of AK RAJ under the topic "Which of the following Rajdhanis are degrading?"