Half-elves inherits the charm and presence elves don't have, and aren't as able as humans to free choice of parameters.
You see, I think its pretty OK to give a break on them. For so much time, Half-elves were only good as Star-Pact Warlocks. And to provide bonuses for everyone else except for themselves. Then the Bard came, and finally there were something suited exactly for them. But still too much "helping others" than solid benefit for themselves. Versatile Master was a bless, but unavailable for the entire first third of the game. And then, Charisma and Constitution are not good for majority of classes. They need to work as hard and will never be as good as other races better suited for their classes. Or even their own. Half-elves will never be as skilled as a melee martial character, since they cannot favor racially atributes as humans do. They would even be a step back in so many choices, this new article is just a fix for them.
Maybe a ranger cannot charge with Twin Strike (even half-elven rangers), but he do can improve their chance to hit as a dilettante can not. There are subtle drawbacks taken with half-elves, no feat till now will remediate.
So I really think these feats are fair and square.
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