I dont like wands either except for being able to use a shield.
So we already had bows consuming stamina. And having range attacks generating focus feels a bit to cheap to me.
95% of the danger comes from fall dmg …kidding … being in melee range.
With the exception of archers and witches (to OP).
So for now you generate a lot of focus by parrying. I mean it is A LOT for just a parry and having enough to cast two spells/skills. In the endgame with + rune generation and cost reduction you might gain enough for 3.
You can gain focus via channeling skill.
There is focus gain on dodging dmg.
What might be feasible is if stats gained additional functions. Like Int would provide 1 focus per second per 10 INT.
But that might come with a HP increase of monster or more resistance (might be specific to zones or type of monster) to combat the wait for full focus and then blast through.