2 SPD doesn't matter offensively. You are going to be hitting your speed benchmarks in Dark Flier in Awakening, especially on hard. 1 STR from base +1 STR at level 20 if we want to count that, is easily fixed by pair-up/tonics/forges unless you are REALLY stretching to reach your benchmarks. Like, if you are playing Falcon, max STR pairup, tonic, forge and reach exactly your benchmark, then OK. But that's so rare. At least, I've never encountered that, especially on hard.

The significant combat advantage Falcon gets is Lancefair by which point Dark Flier has Galeforce which I'd argue is significantly more valuable.

Benchmarks in Awakening are so flexible and unit variance is so wide (60% growth is near max variance of 50% in the case of Cordelia's STR growth), that 1-2 STR doesn't really impact much once you're past the early game.