I agree with everything Dr. Sterling said plus I'd add:
Dire Avengers are meh save yourself points and get 10 guardians with a Starcannon. Less points more damage out put

.
I don't like the all
SL War Walkers give the
SL+ShuriC gets you more So hits and rending on over half those hits and is cheaper the double
SL for me is not a good option. Particularly on such a mobile unit as War Walkers.
SL+StarC or double
BL are for me the best War Walker combos in this book.
I'd also be more voracious in my dislike for Rangers or Fire Dragons. I'd never take either in this codex.
Also Monster Hunter is good on the Avatar. Just Helps him in the match up vs other T6+
MCs. Get Fast Shot first then get MH if you have the spare points.