Lots of questions to ponder over
It could be a malfunction with the solenoid valves for fuel flow in the thursters. They work in vacuum and under earth's gravity, but how does it work in moon's gravity which is 1/6th of earth's and has several dense gravitational spots, weak magnetic field and surrounded by atomically charged particles in vacuum?
Also, the landing region which is close to the S-pole of moon is unexplored. Recently Israel's lander also failed in the same region. Is there an anomaly in moon's gravity and/or magnetic field close to its pole area causing confusion in determining the right orientation for the Lander. What if the orientation turned 180 degrees inverted, so instead of applying brakes on descent, the thursters will propel the Lander with high acceleration towards the moon's surface.
What kind of a gyroscope did it use for orientation determination?
Also, ISRO should have mounted four telescopic expandable/collapsible antennas extending in four directions at 45 deg inclined to the vertical, on the tip of which they could have mounted some balancing and orienting sensors, along with video cameras with signals beaming back to earth via Orbiter in real time.
What about the battery? Is it possible that the battery drained out doing several trajectory maneuvers during descent? Did it have a separate battery pack for communication and separate for maneuvers?