After a long delay, and because I will be playtesting tomorrow, I will speak about another mechanic I found great in idea, but flawed in implementation in a single aspect.
The cantrips, like in 3E, are for the most part small utility spells, but now (maybe as in 4E?) without day limits. All great and well, these utility cantrips are fairly average in power (but allow for creative uses), and though in some of the spells (and cantrips like Minor Illusion) I would scrap the fixed DC for a normal save against spell, the cantrip mechanics are really good.
But there are some offenders to this. For clerics, it is Cure Minor Wounds and Lance of Faith. For wizards it is Chill Touch, Ray of Frost and Shocking Grasp. And while Cure Minor Wounds is a special case, the other four share the same problem, a really high damage input, with some extra effects for the wizard's ones.
First, for Cure Minor Wounds, I think the problem is the cantrip is too weak. But I also think there is a very simple way of increase its power and utility in higher levels, but this comes at a cost at lower levels. To do this, associate the maximum HP the creature must have at the given moment to be healed with its HD. That means that while a level 1 creature (if it don't have extra HD) can have cured at most only 1 HP, a level 20 can have cured up to 20 HP. The cantrip is slight worse in the first two levels, but get better from 4th level and up.
The other offenders, though, I think the problem is that they are too powerful. I had a playtest some time ago, with two player, each one with two characters, one playing the dwarf fighter and the halfling rogue (a fighting player), and the other playing the human cleric and a self-made human wizard (a spellcaster player). The spellcaster player just used a weapon once (the cleric's mace), and even then he failed (and remarked how just really much better is to simply spam offensive cantrips than even trying with the weapons).
The cleric Lance of Faith have a reasonable range, but already in the 1st level cause more damage than the heavy crossbow (the better long range weapon damage), and the same as a greataxe, greatsword, lance or maul (and they don't have a range). Besides, its attack roll is optimized for the cleric, causing weapons to be near useless for the cleric.
A way to fix it is reducing its damage from 2d6 to 1d4, adding the Wisdom modifier of the cleric as a bonus, and increasing its damage by 1d4 on the 7th level, on the 11th level and on the 16th level, to a maximum of 4d4 + Wisdom modifier.
The wizard offensive cantrips too cause much damage, already in the 1st level causing the same damage as a heavy crossbow or a glaive, and ray of frost have a good range too (though the others are touch based).
A way to fix it is reducing the damage of the cantrips to 1d4 (without the Intelligence modifier, though), mantaining the special effects. In the case of ray of frost, reduce the range to 50 feet, and after the speed of the target is reduced by 10 feet, the minimum is 5 feet.
As a final note... I don't have certainty about this, but maybe it would be good to reduce Mage Armor from 12 to 11, as the equivalent material armor is the dragon leather (and is pretty expensive at 500 gp). Treating it as a leather armor might be best. Perhaps, increasing it from 11 to 12 in 10th level, and maybe even from 12 to 13 in 20th level.