Cool. Would you mind going into a little more detail about what feels too strong? Also, how does its hunger and disadvantage on Charm based effects factor into your estimation?
Basically they get everything the Goliath gets, plus more stuff.
I don't think the hunger and disadvantage on Charm are a significant downside in a normal campaign (I almost never see rations tracked, so now you just aren't tracking twice as many rations).
Hunger might be more of a factor in a Dark Sun campaign, which is supposed to be harsher and more survival oriented. But in practice, rations and water were still mostly ignored in the few Dark Sun campaigns I was involved in back in 2e.
Disadvantage vs charms is a hindrance, but not much of one. Most half giants aren't going to be a class that has a good Wisdom score or proficient Wisdom save anyway, so they weren't likely to make the save even without disadvantage. (i.e. giving them a penalty to something they were unlikely to be good at in the first place isn't much of a penalty). It can be significant at low levels (when you have a decent chance of saving even if you have a low bonus or penalty), but changes very little at high levels (where DC's get high enough you mostly fail any save you aren't proficient in).
Plus the standard way of dealing with charmed warriors is still the same - be a Frenzied Berserker Barbrian (immunity to charms while raging at lvl 6), or make sure your party has a spellcaster with Calm Emotions prepped.
On the other hand, Dark Sun is supposed to have more powerful baseline characters in a harsher environment with less magic and manufactured goods. And presumably a lot of people in that setting would be aware of the Half-Giants vulnerability to charms and prepare accordingly.
