I think with streaming services such as netflix/lovefilm and having such tools as XBMC/Plex (specially plex where you can sync your movies onto the device instead of streaming), we will require less local storage for such items as the iPad.
Yes, some people use the iPad as a complete laptop replacement, but for a lot of people this is not a feasible option, it's an addition to their laptop and probably used more frequently, but not for all tasks.
The price for the 128gb is rather high and I don't think on average, many people in the market will need such capacity. 32GB seems to be the average at the moment but saying that it's the middle model of what is currently available, so that will go up to 32gb.
It'll be interesting how the market takes to the new release and whether there be some kind of link between the new iPad and the new Apple TV that will be released (whether it's a box like the current model, or an Actual T TV [unlikely at the moment])
Thanks,
G.