Sarah's voice? I doubt it. She's good and actually one of the better singers in the unprofessional level. Truly a pop singer and should always be pop. But in her defense, she had improved a lot but still cannot perfectly sing classicals.
In the music industry, unless you can sing a good classical song, you are still unprofessional. Sarah's voice is not versatile as you said. She can do pop, rock, and others but try to give her a classical or a high bending several change of keys song. Celine Dion, Christina, etc. are still considered the middle singers even with their high notes abroad.
Sheryn Regis, well can sing classical since she started with it. In addition, Mariah Carey and Whitney are classical singers first before going to easy music (easy singing according to them). So, ranking, Sheryn's quality is still higher than any of her contemporaries. Some music experts say, she's even better than Regine, though not as quite as beautiful as Regine. This is why she cannot be popular in the Philippines. Filipino's judge by faces (try to google it).
Sarah can be Celine Dion but not Barbra/Sandi Patti/Whitney. She is trained as a middle singer. Sheryn on the other hand, if you look at her developments, especially her falsetto, she is becoming something first in the country. The music similar to Josh Groban, Mclachlan, old Whitney, Andrea Bocelli, etc.
ABS-CBN, however, base it on the popular preferences so they are giving Sarah and the others more exposure.
Cranberry, I believe you are not a music major. Try asking music majors and what you shouted on your post is somewhat something they will laugh at.
// Posting on forums with ALL-CAPS is considered shouting. I do like some modernist style but ...
I use fake stuffs but not tampered (cheated) results.
I may be simple but I use my 5 senses. I have my own thoughts and not blinded by a cheater.