+1 to every ability score... doesn't really bother me. A bit bland, but 'eh... The other races tend to have a good array of perks. Not completely balanced mind you, but I think we'll get there.
The +1 to 2 or +2 to 1 or a feat idea? I agree they'd need something else. I'd argue you could almost give them +1 to 2 or +2 to 1 and a feat and they'd still be okay balance-wise.
The thing is, feats are optional, so you have to find a way to compensate humans without using them.
You raise a good point about Feats being optional, but Skills are also an option so Lore would also have to be off the list. And as Warbringer points out, it is a little odd to see Humans know more lore than other longer-lived races.They might be alright balance wise, but it brings us back to the central issue of why we're facing +1 to everything humans in the first place. If feats are to be entirely optional for the people/groups who refuse to use them, then we cannot give one to humans. As an option, alright, but not as an assumption.
So then we'd be giving them two ability increase? A little better than +1/all, but not much.
Perhaps an ability increase (with feat option) and a lore? Or a proficiency (weapon, armor or gear)? Or both?
They're adding a little extra stuff here and there that I think gives us a little more leeway than we used to have.
The thing is, feats are optional, so you have to find a way to compensate humans without using them.
How about limiting it to cultural lore to celebrate the diversity of human cultures.
Anyways I took a good look at the Mage and those worried about Sorcerors being forced to use spell books is unfounded as its tied to Wizardary itself so if you choose Socerory or Witchcraft instead then they can have other machanics instead.
The only universal part of Mages is Estroric Knowledge, Brew Potion, Scribe Scroll, and Spell Mastery. Every thing else is tied to Arcane Tradition and what ever catorgory wizardary is. So if you pick Sorcecery and then pick say a dragon bloodline then the only things in common that's have with someone who picks wizardary school of illusion would be the Mage Spell list, Brew Potion, Scribe Scroll, Estroeric knowledge, and Spell Mastery. Everything else could be radically different.
Also note in 4e that witchcraft was actually a wizard subclass that game mechanics wise had nothing to do with the Warlock class.