Subjectively, I'd say Titanfall is a 1/10 for my tastes and Destiny is a 4/10 largely due to having a single player mode so I might get it for $5 in a bargain bin in 2017.
Objectively, I imagine both will score at least 80s and possibly low 90s with Titan Fall edging it due to releasing earlier. TitanFall - 92, Destiny - 88
On sales Destiny gets the edge as many have pointed out it will be available to far more gamers being a multi platform. Shot in the dark? Titanfall sells 2.5 million, Destiny sells 5 million.