Those are good questions. With a longer fermentation there is a greater opportunity for the biochemical activity to produce a dough that is more extensible (stretchy) and a crust that has more flavor, better texture and greater aroma. How long it will take to produce these results will usually depend on the particular formulation and the dough management procedures used. Someone with a good palate will usually be able to detect the difference between the results of a short fermentation and a long fermentation. However, as we get older, our tastebuds become less sensitive, so we won't always be able to detect some of the subtle differences.
The differences between a room-temperature and a cold-fermented dough will usually be time related. The same kinds of biochemical actions take place but the rates and extent of the biochemical actions will be different because cold fermentation slows down the fermentation process considerably. Undoubtedly there are some differences even from a biochemical activity standpoint but given enough time, I suspect that a properly managed cold fermented dough will end up similar to a room-temperature fermented dough in terms of dough texture, crust flavor, etc. What is often not noted is that cold fermentation is often used as tool for dough management, since it gives the pizza operator greater control over the dough, helps with dough inventory management, etc. Otherwise, the pizza operator will have to decide at the end of the day what to do with all the leftover unused room-temperature fermented dough balls.