I like the instant elevation profile for route creation where Google Bike isn't available, and the generally pleasant interface, but question the sources of the routes. Shortest distance isn't always the best for bikes, I can punch in a few routes and have it take me on very bike-unfriendly roads. Otherwise if I am using the Google Bike layer, I don't have much of an incentive to go to it instead of Google Bike.

Any way to plug into data sources like Strava heat maps? Also, as others have mentioned, offering multiple routes past just the shortest? Maybe a scenic option? I did a nice ride this past weekend, where just a couple miles more resulted in a breathtaking lakeshore drive, instead of a ride through monotonous farmland that this would route me on.