That's a big reason, indeed; I can't deal with those two things being garbage in a game that is pretty much all about the online component.
I mean, that alone would be an absolute deal breaker for me, but it's not just that, even. Treyarch to me just makes boring games. I played the shit out of MW1 and MW2, and now I'm addicted to Ghosts, whereas none of Treyarch's games lasted very long for me before I got bored of them. Even MW3, arguably the blandest COD made by IW, lasted me so much more time than anything signed by Treyarch.
What really makes Treyarch's games unappealing to me is how little variety there is. Pretty much every weapon within the same category feels the same, the perk balance is usually stale and offers very few class possibilities (all in the name of being competitive, not realizing that COD always had, and always should, revolve around fun), and after three games these guys still seem unable to come up with any relevant new perks to spice things up (unlike Infinity Ward). The end result to me is always a "been there, done that" feeling when playing Treyarch's games, and while that could be said about COD overall, at least Infinity Ward's products always seem to switch things around just enough to keep things interesting (really loving the new perks in Ghosts and new additions such as the Marksman Rifle weapon category).
Three games Treyarch has had to win me over; three chances to at least finally get the hit detection and netcode right, and they fucked up. I would have to be a fool to give them my money again.