I thik with such places with restricted access things slow down gradually with time instead of improving. For eg Silguri Alipurduar when commisioned in 2003 avg speed was70-85 kmph but now avg speed has drastically dropped down to 35 kmph. In case of Lumding Badarpur too please keep in mind that in future trains will increase so as the crossings. So by all probability avg commuting time is going to increase.
Yes I do agree with your opinion that MG is thr perfect choice in these cases but IRs unigauge policy is a nightmare