To be fair about the matter of textbooks on Philippine history, I do know of at least one book whose treatment is a little more balanced than the ones I used in my time. It's Paul Dumol and Ernesto Grio's "A History of the Filipino People for High Schools." I've been fortunate to have made Mr. Dumol's acquaintance many years ago so I trust his work implicitly. A reading of the text only serves to confirm my initial impressions.
The central theme of the textbook is the development of a common cultural identity for the Filipino people. Early on, the authors already establish that at the time of the arrival of the Spanish, there was no common Filipino people, just various tribes. Their story of a more organic development of the Spanish colony is far more believable than the image of out-and-out slavery that seems to be the common mental image.
Even more interesting, Dumol and Grio also tackle the impact of the Dutch Wars and the British invasion of the Philippines. Both of these had a significant impact on the relationship of the colonial Spanish with the Malay natives.
As the story progresses to the 19th century, we see the maturity that the country is going into, along with the attendant problems. This, of course, leads to the the period that is the typical focal point of Philippine history as taught in schools. But by then, we have a more complete picture.
My only complaint of the textbook is that it is rather thin and lacking in the details. It reads like an outline, really. I was able to read through it all in one night.
It would have helped greatly if there was a more extensive treatment of pre-Hispanic Philippines as well as presentation of the broader view of the developments in Europe from the 17th to 19th centuries that affected the colonies. But I guess that's what further reading is for.
Unfortunately, there's no online reference to the book, but economist Dr. Bernardo Villegas did write an extensive review in the Manila Bulletin a year ago.