I agree with this. Nerfing the starsigns that make a real difference is not interesting, it would be like removing the starsign feature altogether. Buffing the starsigns that do almost nothing is the way to go.
Tree is already quite attractive after the buff, I can think of characters where I would want it. The other useless or almost-useless signs should be made interesting in a similar way.
BTW, Cup is useful IMHO. The extra talent really makes a difference in the early game, whether you use it to get the indispensable TH earlier, or to get some defensive talents to survive the early game with weak chars while leaving the possibility of TH open for later. The extra exp is not bad for those of us that don't scum, and magical learning can't hurt.
The useful signs right now are Candle, Raven, Tree and Cup, and the rest are just not worth it and should be buffed IMHO.