Hiking Project has been an amazing community treasure.
The iOS app shows only two layers- a satellite and a generic map layer. While the generic map layer shows terrain information when sufficiently zoomed out, the contour info is not readable. I wonder if its possible to get those excellent layers that are already available on the website (NeoTrek, OSM, and Terrain) on the mobile app as well. If so, then hikingproject can become a pretty viable alternative to apps such as Gaia GPS.
You bring up an excellent point, and I have some good news for you! We've been using Google Base tiles for quite some time, and we're a bit limited by their use conditions. Because of this, we're currently working to switch to a new map provider. As a result, we're hoping to get more base tiles available in the app, and are hoping to be able to download the tiles to our app instead of relying on caching. The new maps are in their finishing stages, and should be mostly available online, however it may take a little longer to get the new maps in the app. It should be on its way shortly though!