This was to be expected. The federal government is consolidating NSERC, CIHR, and SSHRC doctoral awards into one program.
The NSERC PGS D, NSERC CGS D, CIHR CGS D, SSHRC CGS D, and Vanier CGS D were all 3 year awards. The only award that was 4 years is the SSHRC Doctoral Fellowship. In the end, those with the SSHRC Doctoral Fellowship are getting a 50% increase from 80k to 120k, and it is important to note that rather than waiting 4 years to get 80k, you will get 80k in 2 years which really makes a huge difference.
Of course it would have been amazing if they were all increased to 4 years, but that would probably be asking for too much with the increase in award values and the eventual increase in award numbers in future competitions.