I recall from past experiences that others posted here that YOUR visa status in the Philippines also is a factor. If you have permanent residency in the Philippines, and the visa to prove it, that is some evidence to support that your wife would return to the Philippines with you and not and not overstay in the US.
I'll also mention (and this is from personal experience) that US immigration makes some decisions that are seemingly not based on common sense. Our daughter's grand-mother-in-law, a widowed Philippines citizen, was eligible to be petitioned for permanent residency in the US because her daughter (our daughter's mother-in-law) was a naturalized US citizen. But she really only wanted to visit her grandkids in the US for a few months. You'd think her status would give her a leg up on getting a tourist visa, but no, they denied her, on the grounds she didn't have enough ties to ensure she would return to the Philippines. So her family went ahead and petitioned her and she got a green card, even though that was over kill for her situation.