your concerns are unnecesary. the train goes on an almost full-length double electrified track. these stops wont slow the train by more than 10-15 min max.
the old tt had too much slack. infact the tt now has improved.
stops at kjm and bnc are vital for a city like blr especially and especially because train leaves at 5pm from sbc.
the train is...
more... now far more useful to a lot of people.
the only downside if any is that a lot of non-reserved people get into the train. but thats still ok. better than having a normal train have no stop between SA and SBC
even the shatabdi has a stop at BNC!