It's a math issue. Leaders don't in general fix the issue because they don't grant attack bonuses nearly frequently enough to compensate; and generally don't grant such bonuses when they miss. And of course, not all parties will have a twinked out specialist attack-bonus granting leader; some leaders grant very few attack bonuses, and often can't grant those to just anyone.
With the numerical change, the game plays better. It's not impossible to play without them, but the change certainly improves gameplay: it's fix for the math. If you don't look at these feats as math fixes, the alternative conclusion is that they're horribly overpowered, bland feats (and that grind is good).
It's not just leaders, most classes have buffs/debuffs going. My Thaneborn Barbarian drops someone? Hey, burst 5 defense drop for a round. Human Wizard is dropping a +6 attack bonus on everyone against a target for a round. On a miss even. The bonuses are there, but the "moar damage" tards look right past them and then whine about their attack bonus while ops want them too.
They're very good, but unnecesary if you take advantage of the game as presented. They give you flexibility if you can't/won't/aren't taking advantage of the opportunities built in to the game. And they have nothing to do with "grind" another moronic net term.
I will agree they are bland as heck though.