Skywriter, there are three 'kinds' of miracles.
First: The sort of thing we call miracles. "The miracle of life", speaking of a newborn baby, or the baby growing in the mother. Actually, it's a pretty 'ordinary' miracle in some regards. Not that 'we' (humanity) can explain it, but it does happen rather frequently.
Second: The sort of thing which cannot be explained through ordinary, rational thought. Jesus walking on the water comes to mind. Of course, there are some attempts at explanations, but they tend to fall flat when examined. Jesus raising various people from death: The daughter of an unnamed 'ruler' in Matthew chapter 9 and others. What can be labelled - and please excuse me - 'flashy' miracles.
Third: Those things that happen which just 'seem to happen'. Like being cured of liver cancer. No one 'sees' it happen, but it's gone! The money which appears when one thinks "I'll never get this paid". This is the common things events that seem 'miraculous' to those who know the inside story, but not to the casual on-looker. Finding one more piece of pizza when needed. That sort of thing.
I agree. There are some things which are unknowable. At least in the sense of solving an equation or demonstrating a chemical reaction. But those who have the inside story are aware 'something' happened outside the normal channels.
Then there are things such as rain. Common, every day water falling from the sky. Not what ordinarily classifies as a miracle, but the timing is notable. And rain happens because the wind, atmospheric humidity and dew point all 'just happened' correctly to cause rain in a certain place at a certain time.
I do not think God is unpredictable in the sense of erratic. Normally, dead people don't come to life and leave their graves or the mortuary. Normally, Tuesday comes after Monday. Normally, one doesn't plant wheat and harvest a Camaro. Normally one doesn't plant wheat on Monday and harvest it on Wednesday of the same week.
But 'stuff happens'. Just usually God doesn't do miracles with a drum roll and a fanfare.
As C. S. Lewis pointed out about the miracle of the wine you cite, God did in a few minutes what normally takes the better part of a year. Which is not to minimize the miracle, but perhaps to emphasize it and make it more personal.
As for 'healing', God heals all, whether done while no one is looking, or with the assistance of six or seven doctors and twenty nurses; three hundred pounds of medicines and a whole hospital full of special equipment. Figuring out how planets or suns are formed does not lessen God's work. Especially when God uses gravity and not bulldozers.
