My take on this is that the LTA as the body that oversees the SMRT should the the one to be blame, more so than SMRT. Firstly, who is responsible for the influx of foreigners into Singapore, such that the MRT is literally bursting at the seams to accommodate the increase in passenger loads. SMRT said and rightly so, it is not so bad and the capacity is not yet "crushload."
Then LTY with a new portfolio as Transport Minister due to pressure requested for an increase in the number and frequency of trains to lessen the traffic. Has SMRT a choice? SMRT started in 1987 which was 24 years ago and as far as I can recall, there had not been any major overhaul or replacement since then. Obviously, originally designed for a smaller population and not taking into account of a population explosion, the MRT succumbed to the stress that it was not designed to absorb.
LTA should have done a proper study and re-look at it in totallity, being the body responsible for the transport system to serve the needs of the population. Ultimately, the responsibility lies more with the government than SMRT.