My problem with Protestantism is also what I respect about it. It offers all sorts of alternatives. Mainline Protestantism as a whole is very 'big tent'. Its churches have liberal Unitarianish types as well as conservaive evangelicals. The line is not drawn on theology, but basically on fulfilling the two commandments of Christ - love God and one another. Remember how the lawyer asked Jesus how to gain eternal life? Jesus did not answer believe this or that. He gave the two great commandments, then illustrated them with the parable of the Ten Commandments.
I'm inclined to think that human beings (and their churches - all churches that are dogmatic) simply aren't equipped to understand the ultimate realities of existence. Some day - maybe - in heaven all of us are likely to be surprised. We'll be joined by Catholics, Protestants, Orthodox, Jews, Muslims, Hindus, Buddhists, those of Native American faiths, and millions more of various religions. This notion that there is 'one true church' is unrealistic, uncharitable, divisive, demeaning, and too often bigoted. Sadly, many traditionalist Catholics and fundamentalist Protestants feel that they have the truth and the rest of us don't. Silly arrogance.
Most Catholics and Protestants I know embrace the theme: "think and let think". If you love God and love one another, let us walk together without fighting over piddlings. Did Padre Pio really belocate and levitate? And I've read there's enough relics of the true cross to make dozens of huge crosses, enough relics of Mary's clothing to make a huge wardrobe, etc. As for Pentecostal Protestants, when I see Benny Hinn, Pat Robertson, Tilton, and others, I have trouble believing them, too..