For the record: Bashing others because of what they like, while yourself know next to absolutely nothing about it, is plain sad. I feel sorry for you.
Oblivion is what I'd call a perfectly composed coaster. It is fast, no need to make it faster, the hole is pitch black anyway. It could have gone faster, but it is fast enough to achieve the desired effect anyways. More speed wouldn't have added anything to the atmosphere.
There is no need to make it taller. The entire focus of the ride is on the hole, anything before that is plain filler. But it is tall enough to make people see that it is fast. And steep. And it is tall enough to make that "fall into the black hole" feeling.
And a nice themed area around it really completes the ride.