If you observe train routes and timings, no train passes through Bangalore to other cities (for example JTJ SA towards DVG/ DMM side). This is because of loco reversal at SBC or at SMVB. At SBC, no link to JTJ and YPR lines.
These restrictions lead to less connectivity.
If BWT Chikkaballapura line gets linked to DMM line at Gauribidanur/ Hindupur, part of problem can be solved. If Devanahalli Doddaballapura gets linked, it is also ok. If Doddaballapura gets linked to Tumkur line, it will be superb.