Nifft
Penguin Herder
The difference here is one person adjusting numbers vs. four people adjusting numbers.Isn't it simpler to just give a bonus to all attacks from PCs? Mathematically it's the same and you just have to adjust the values for the characters instead of all the monsters.
In 4e, monsters aren't all that complex. Adjusting the defenses of 20 monsters is quick & easy. However, PCs are complex. There are powers that give an explicit bonus to attacks (so "attack" isn't just one number); there are Implement vs. Weapon powers; there are racial powers; there are magic items, racial features, class features and feats that give situational bonuses to certain types of PC attack rolls.
Lots of variables go into a PC's attack bonus, and they can differ for different powers. That's a lot more difficult to validate than a monster's defenses (which are level +/- mumble mumble). There is a tool which helps players to do this validation, but it's closed and inflexible. I don't need a tool to help me calculate monster defenses, though: that's easy.
Basically, adjusting monsters is easy work which only one person has to get right; adjusting PC attacks is complicated work which many people have to all get right.
Why pick a hard way when the easy way is ... well ... easy?
Cheers, -- N