Size matters, HOW MUCH it matters depends on your skill level, like it was mentioned AND your game plan.
Reach matters a great deal in the striking arts, take thins from a 5-6 fighter
Some guys have arms longer than my legs !
Kicking is irrelevant to beating the size game, it actually plays in favour to the bigger, taller fighter, pretty obvious.
You wanna get IN on taller fighter, not stay outside where their reach advantage and size will count more.
Fast hands mean crap if you can't get in, you need good foot work to get in, you need to be able to move off his move, go to the outside to get inside, you need to fight YOUR fight not his.
I can't over emphasie the importance of footwork when facing someone bigger.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !