Okay...
There are lots of broken combos already. I know, however I don't thing they are that big deal. Many combos are kinda like a frankenstein monstre, which at the end no character is done, but a walking combo. Even for D&D4 I think games should be played by characters, not walking combos. And even waling combos have had sacrificed many other advantages, and gained a lot of weaknesses in return
I also know their (half-elf) Stat may help him as one of the defender classes, a Paladin based in Charisma. Oh well, maybe not in being a good defender, but being a good Paladin. Con never hurts, true. But seems to be prime for a melee combatant have raw striking power, and then, good defenses, and last good HP. Raw power helps in killing foes faster. Dead (not undead, lol) enemies don't strike you back. Good defenses help you avoid being hit, even when they DO strike back. And good HP helps YOU strike them back. Cha stands for secondary or tertiary stat, unless you are a caster or Bard.
About feats, Half Elves' feats tend to be more partner friendly than really useful, unless those which enhances their racial power. Humans' feats tend to be meh, except for action surge. And the better feats from elves enhance their Elven Accuraccy racial power, and Half-elves DON'T have acess to that power, although they can acquire those feats anyway
I hope half-elves can choose STR instead of CON, making them suitable Cosmic/Dragon sorcerers. AND making them also good melee martial characters. After all, seems a bit strange an entire race handicaped for martial training.