Exactly my point. Why do I need "priestly shield" to have a special power when you can have the same effect by saying "priests can attack with X bonus". It almost seems like they're actively discouraging "mundane" weapon-play.
Because 4E is working through an Exception-Based rules system, instead of an Inclusion-Based system.
In 3E especially players were encouraged to have a single tool and pile as many special abilities on top of that tool as possible, a wizard was encouraged to boost his spell save DC's as far as possible, because you had a single ability (provoke a save with your spell) that was modified incrementally by inclusive effects (take a feat to boost your DC, boost your int to increase your DC, etc). Nowhere is this more apparent than the mounted combat character, who pours all of his feats, abilities, and equipment into having as high of a charge bonus as possible, and then applies that trick to all his attacks whenever possible. The same thing is present in Rogues who boost their SA dice, and on and on.
Each ability in 4E is doing is saying "here is an ability, it works, here is another ability, it works too. But you're not allowed to blend those two abilities with a third and create something broken" So a Fighter does not get a class ability of "add 3 damage to the fighters melee attacks" and then a Daily ability of "once per day the fighter may deal 3x damage with a melee attack" because those would be
inclusive abilities. The fighter spends all his resources to boost his basic melee attack as high as possible, and then sometimes triples that damage. Instead he gets an at-will ability of "make a melee attack, add 3 damage to it" and a Daily ability of "Make a melee attack, deal 3x damage with it".
The reasoning behind this method is pretty simple, really. It's
incredibly difficult to balance inclusion-based rules systems (possibly impossible, because there's almost always SOME number of abilities that, when combined, grant geometric power growth). This is why we have Weapon Specialization, which is nice for a 2W fighter where it can give him +20 damage if he hits with 5 of his 7 attacks for the round, and
totally OMG broken when it gives that optimized pouncing charge fighter build an extra 100 damage because he hits 5 times for x10 damage in a round. If instead you make a TWF ability tree that slowly increases the damage bonus for each attack made from +1 to eventually +4 that will work out well for him. And then you make a charge abilty tree that grants bonus charge damage from +10 to +40, and you're assured that the player won't grab 10 different splatbooks, pile them all on top of each other, and fuse them, voltron-like, into a single ability that deals 10,000 damage and provokes four different save-or-die effects.