As men age, and the prostate enlarges, it's not uncommon for the intensity of orgasm to diminish. Medications can also interfere with the feeling. It's a bit unusual to have little reward in the teens and twenties. If you have, indeed, always been this way, you may never have intense orgasms as you would have already experienced that by now. On the other hand, if the intensity has diminished over time, it might be aging and/or medications. As the prostate enlarges with age, it can't contract quite as effectively which can interfere with some of the intensity of the nervous response. Take a look at medications (blood pressure and anti-depressents) which can diminish the experience. And try warming up the prostate with a hot bath to relax the muscles a bit. And remember that comparing "wow" experiences is too subjective to mean anything. There is also a psychological component. "Thinking" about the experience can interfere with it as can preoccupation with satisfying your partner.
men don't experience the big orgasm. perhaps refrain from ejaculating for a week and then you'll experience a more intense orgasm.