So having two parents as teachers, and my sister is also a teacher, I can tell you this first hand. Class size and special needs help is HUGE issue. It's severely effecting kids educations, especially in the elementary and middle school levels. My Mom in last year of teaching had five special needs kinds in her class of 34ish students, and it almost drove her to stress leave, and she never quit anything in her life (a aneurysm burst and killed her the end of that year, coincidence?). Teachers are also very underpaid for the work they do, and the time they put in. More so at the entry levels, but still at the upper level.
Also, don't fool yourself into thinking the BCTF truly represents teachers interests either. I mean they do in certain respects, but they're also they same union that's keeping the bad teachers in jobs. Also, seniority rules for all teaching jobs, which isn't necessarily a good thing in teaching. My Dad was an administrator (principle), and he found it next to impossible to fire a teacher, or to hire one who he thought was best for the job.
I guess my point is change is needed much more widely than just contract negations. Yes, teachers need better contracts (which should only focus on salary, benefits, etc.), but also major changse is needed at both the Provincial level, and at the union level.