Popped in my DVDs to rewatch some scenes, just to make sure my memory was correct:
Obi Wan's starfighter did manage to avoid most of the fire lanced at him by Jango, with many of the blasts exploding nearby him but not directly on his shields, and many hit a lot of the rock floating around (they explosions are too far away), also note that Slave I has rapid fire, low powered blaster cannons, not military grade lasers.
As for the Falcon, A) It's a much larger ship than the fighters and would naturally have better shields I'm sure. Secondly, having watched that scene the falcon is only hit 3 or 4 times by lasers anyways, and none of the turbolasers hit it.
In general, the most commonly seen fighter combat has it being quick and deadly, a style of play that we've chosen to stick with. The only scene that is in any of the movies that could really show it differently is that one scene in Episode II, and at the very most all you could use that as comparison of is simply between those two ships. Prequels don't override the original trilogy in our minds.