Foldable bike support
None of the transit apps supports using foldable bikes. In this mode, you can cycle to a subway station nearby, use the subway, and then use the bike from the nearest subway station to your destination. Basically, cycling replaces walking to and from the stations.
Paired with routes that minimize changing lines such a feature would be swell

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Anonymous commented
Many transit providers where I live (San Francisco Bay Area) allow full-sized bikes on transit. I often reverse directions if I want to take transit for the first leg of a trip. Because TripGo assumes I have to lock my bike before getting on transit, it will offer bike + transit on the way back but not on the way there.