Haven't seen Strange yet, but I actually feel like that's the one thing I can confidently say that Deadpool will do better than Strange (well, that and maybe the humor, but we'll see): the love story. Deadpool succeeds mainly due to the genuinely touching, if somewhat undercooked, romance between him and Vanessa. Deadpool is a smarmy, nearly invincible jackass whose schtick could grow very tiresome very quick, but the love story made me actually buy into the character and his journey.
Strange could have a great love story, I haven't read anything about the film and I don't know what to expect, but Deadpool's success, in my eyes, is due entirely to the romance.