To be noted is that with the Soul upgrades, Solomon is now quite the beast. She can deal ridiculous damage in a single turn, though damage caps might hurt her. She might be able to kill even F8 solo...
My Solomon can deal ~2m-ish ability damage in a single turn (I think, the only opponent I could test this on is Water Rag), and this is with zero debuffs on the enemy. The question is, to bring her to F9 and F10 or not, as those floors have bosses that have roughly 3m HP I believe. The ability to 0-turn the trash alone might make Solomon plenty viable in those floors already.
And if you do 10/15 floors with Solomon, then it's no wonder people have talked up Solomon so much. While she was bloody useless in Fire Tower, she's going to be damn good in all Towers after Second Anniversary update.