I always love playing campaigns myself. Without knowing HOW the campaign goes online with Titanfall, I can see complaints about not having a solo experience. If the story is well-done online, I can accept the $60 price tag, I suppose. But when Halo gives you a solid story with reasonable Legendary difficulty, plus good online and Spartan Ops, it's hard to say I want to spend the same amount for JUST the multiplayer aspect.
Plus, while CoD doesn't offer the same quality of storytelling, it gets more flak than it deserves. I like the Black Ops II campaign, just because of the great things they let you play with--all of the tech and whatnot.