good question. my thoughts:
I have verry little upper body strength. so I find that I rely mostly on technique. I have powerful legs and that is where the majority of my strength is. I learnd alot this summer climbing with way better climbers (thanks Tex) and actualy top roped a real 5.10 with out falls... granted I worked on it for more than a week, but that was a big break through for me.
truth be known, I HATE TO WORK OUT! HATE IT!!! but I think to progress any further I will have to seriously start to work out, (and not sparadicly) to build strength and endurance.
so bottom line you need a good balence between strength and tecnique... it doesn't hurt to have a good strength to body weight ratio either. I have watched JK start climbing after me and totaly out class me due in part to his strength and size and his natral ability... he's working .10 and .11 now. I suck