I would really like to see more support for adventures that are run nearly entirely text-based, allowing for more chat windows for conversations between individual characters and players, as well as the ability to move around individual "windows" like the map, and pull out multiple tabs into their own windows. There are plenty of ways that Roll20 could facilitate text-based adventures, and I think allowing for an experience similar to MUD systems would generally be conducive to that style of play. Multi-monitor support recommended for this.