Depends on how it's implemented.
For as much flak as X7386 received for his
mathematical analysis of lava hounds, I thought he had some brilliant ideas in there.
First of all, I think my favorite part was his analysis of lava pups:
That's pure genius right there. Sure, the hound spawns 12 pups. But that doesn't mean that the pups represent 12 housing space.
So what about skeletons? Do the 8 skeletons of level 2 witches really count as 8 housing space? If they did, the witch herself would only be worth 4 housing space, basically a wizard.
So here's the thing. A skeleton's health and DPS are frankly rather pathetic, compared to a barbarian. DPS is similar to a barbarian, but they barely have one-third the health. They get one-shotted by maxed archer towers, and by level 10 cannons (available at TH8). Note: not sure about level 9 cannons, the DPS suggests 44.8 damage per shot, and skellies have 45, so depending on rounding, they might get one-shotted. Does anyone know for sure?
Anyway, the point is, 8 skeletons is not worth 8 housing space.
Using X7's math, the geometric mean of 25/30 and and 45/125 is 0.5477. So 8 skellies are worth just over 4 housing space. Let's call it 5. It kinda just depends on what's attacking. Against low level point defenses, 8 skellies might only be worth 3-4 housing space. Against heroes that will one-shot barbarians anyway, skellies might be worth the full 8 housing space. But 5 seems a reasonable average.
Now, what about the witch herself? She's slower than a wizard, has less health, and lower DPS. The only thing she has going for her is her range, a full tile longer than wizards. Without the range buff, she's really only worth 3 housing space at best, maybe even 2. Considering 12 housing space, minus 5 for the skellies, she's worth 7. Does the extra tile of attack range justify her being worth 7 housing space instead of just 2-3?
With all that out of the way, I think we have room to argue for a level 3. Bumping her up to 10 skellies would mean that the skellies are worth closer to 6 housing space. That makes the witch worth closer to 6, which is probably more in line with her actual worth (as a longer range, very weak wizard).
So yeah, I think there's room for a level 3 witch, and based on math, I don't think she'd be OP.
Of course, the math ignores most game mechanics (I tried to consider a few), so it doesn't
really tell us if she'd be OP. But it at least let's us consider it.