Rankett Proving Ground

With the addition of new 2 cc homunculus ally, Frost Flame Harpy, this location become problematic. If you draw it early, you could easily grow big allies while at the same time gain a card advantage.

-At T1 you cast Gremlin or Rotling
-T2 casting Frost Flame Harpy is preferred or Sword Gobbler
-T3 stop sacrifice, cast Rankett and cast another Harpy, now you have 1/4, 2/4, and 2/5 ally and also a card draw while your opponent still have 2 or 3 resources to answer all that. If you don't have Harpy you could cast Spontaneous Growth, or Crystal Shard/Splicer Crown, not as solid as Harpy but still quite good.

I suggest a balance change for Rankett to: T4, 1SE: If an ally gained base attack or health this turn, draw a card and target Homunculus ally gain +1 base attack and +1 health

Basically you pay 1SE to draw a card and gain +1/+1 for only one ally which is already a good deal, while T4 I think it's reasonable time for the opponent to have a board presence to counter the location fairly. Let me know about this suggestion for the balance change

The key to countering Rankett is generally to spend 2SE to take the location from them. You can also play your own location on top of it. Homu also have a huge draw power problem and generally play cards like Bad Santa. They are very vulnerable to cheap removal like Retreat, Crippling Blow, Now You're Mine, etc. I don't think they are unbalanced but you do have a point in that they are kind of un-fun to play against (just like most rush decks) because there is generally not a lot of back and forth play and it also just outright wins many match ups. I could see a minor nerf being exiling the location instead of taking control of it or something along those lines but I think your proposed nerf is too harsh.