I'm sorry to say that at 23 months DS is getting worse rather than better with night waking. Last night was particularly bad. I too second the night time potty-ing. It settles him down quite a bit, and I potty him when I can haul myself and DS out of bed. I'm often too tired to do so.
We have gone over everything too to see if it had to do with his environment (bedding, clothing, eating, etc.), but there seems to be no consistency other than that he sleeps particularly lousy after we eat pasta and meat/tomato sauce for dinner.
I too am finally beginning to accept that it is DS's temperament rather than anything else. Sometimes, I have to dig deep in my positive emotional stores to keep being sweet mama during night wakings. I still nurse when he wakes and sometimes he nurses all night. When it gets bad, I tell myself that I'm still resting. DH is not part of the night time parenting, because he needs his sleep to function at work. He sleeps in a different room. Anyhow, you're not alone, and who knows, for you and your family it might just be a short phase.