Weird, I really haven't had any kid of deflection, even in thin blades, in many years. The newer blades may deflect, but they just dont deflect to where they effect anything I make. I simply don't worry about it like I did 15 years ago.
I always use the largest blade or bit I can. This is because at the same RPM the larger diameter spins faster and spinning faster in almost every case gives a better finish.
Even in my under powered universal motor bench top table saws I get the best cut out of 10" blades and only would go to a 7" if the project dictated it.
Using smaller blades won't hurt any saw I ever used.