More talent makes it easier to coach effectively, makes things easier on the QB, and makes preparation that much smoother.
Especially when you talk about true marvels at their positions like Suh. The QB position being the ultimate bottleneck is still absolutely true, but I don't think it's a stretch to say the rest of the AFC East teams loading up on talent can prove to be a threat to the Pats.
Speaking of talent, I really wish people would stop saying the Bills D was good without Alonso, therefore they won't miss him. It's such short term thinking. The key to great defenses is consistency across the seasons. Alonso could have been a fixture in the Bills D for a decade, which was his real value. If the Bills defense had any weakness last year, it was lbs in coverage, which was Kiko's strong suit.