Reverse direction is something I'm slowly working on!
Road-only and less 'around the houses' options are unlikely for now. The route-planner works by pregenerating the ideal routes for lots of A-B combinations (a technique called 'Contraction Hierarchies'), which is why it's so fast when dragging a route around - it's not recalculating every time, it's looking up most of a pregenerated route. This requires a lot of RAM - about 30GB for the full dataset. (The pregeneration process needs 128GB - I have a very noisy server in my office which I fire up once a month to do that!)
Adding a new route option would mean another 30GB dataset, which means renting another heavy-duty server, which ain't cheap. There might be ways round it in the future but they're not realistic at present, I'm afraid. I am doing a bit of work to make the routes less wiggly in towns, though - I'm currently engrossed in the internals of OSRM (the route-planning software) reworking its turn logic...