I imagine from the way supporters talk about it that the new trolley will have a more nostalgic feeling. Which would be oddly out of keeping with the way the architecture is going. I think your depiction is cool but it looks like a high speed train (where is the train from?) I think something that looks like an open bus would be more appropriate to the scale and use of a downtown trolley, short trips, on and off. Not so imposing on the streetscape, visually and physically.
If (or when) downtown becomes multi-level (Grand Avenue will have some multi-level aspects) the trolleys will have their own level separate from pedestrians. But pedestrians should always be the number one priority Downtown if we want a living urban environment.
One thing your pictures don't show is how different the architecture will look in just a few years. Based on other posts here we are going to be living in a very space-age city where the ground plain is not so obvious and buildings work to break up the street lines instead of reinforcing them like the old buildings do. Like books on a shelf. The new buildings involve surface and volume in a way to activate the larger volumes behind the sidewalk and make them part of the urban dialogue in a way we haven't seen yet very much. Disney Hall is a good example, if extreme.
I also think there will be far fewer cars on the street than we have now, most will be taxis or limos, and alot more pedestrians. Private autos will seem so, well, suburban, you know, 20th century. Really backward and square.
The trolleys will share the street with bicycles, buses, shuttles, people walking, Segways?
-Tim