Canon has already delivered a great 16-35 f/4, a spunky new 24STM and a great 100-400 update. 2014 was great.
2015 is off to a good start with the 11-24/4. I'm itching to see how it performs.
In terms of what I'd like to see updated next... well, the prime suspects have to be the 50/1.4 along with the 35/1.4.