Wet-heat cooking intensity vs. time Dry-heat recipes have a variety of options for low-slow vs. high-fast cooking. Techniques like searing, caramelization, smoking, etc. all contribute special characteristics to the end result.

For wet-heat recipes (steaming, poaching, boiling), would there be any such differences? As long as the food is properly controlled for internal and external temperature, does the process used affect texture, taste or appearance?

I can think of a few differences for delicate foods, where vigorous boiling would destroy the texture. But that seems to be more of a control and timing issue.
Not sure I understood your question correctly.

Yes there are differences. 
1)soups and stocks. If you boil a chicken soup in will end up cloudy. If you simmer it will be clear. 

2)rice. The proper way to make rice is to get it up to heat then cook covered on low heat. If you were to boil, the outsides would be destroyed/mushy and the insides would still be hard. 
I'm sure there are many other examples