It obviously depends on where you are, but a lot of people have been recommending
Lumatic City Maps as a replacement for transit. Personally, I actually had switched to using a 511 App (SF Bay Area Transit) a few months ago as I found it was much more reliable in timing than Google Maps. Still sucks to not have integrated transit in the maps app though.
I'm in Seattle. This looks like a very nice app, but unfortunately, I wouldn't be able to use it as a replacement because 1) it can't find certain locations, like my university campus, and 2) it can't find the bus stop right next to me, so it's telling me to walk 9 miles. A shame, considering.
Tons of people have been saying this, but I don't quite understand it. Why don't you use a dedicated transit app? Do you constantly route your trip in order to get the transit info? For me, using a transit app is way more efficient at getting bus and train times. I already know how to get where I am going since I've been living in this city for a while, I just need to get the schedule for transit. Did google maps let you just look up transit times without having to constantly set a destination, or set favorite stops? I don't remember being able to do that.
I have yet to find a single transit app that works well for Seattle. Google Maps always instantly finds locations and public transit routes, and can be used to open direction links from Safari. It also works when I'm in other countries, especially important since Seattle is only my current place of residence. If I'm ever on vacation anywhere as well, I know I can rely on Google Maps.
I usually tend to route my trip since there are sometimes buses I didn't know I could take to get to the same place, crucial if I had previously missed the bus right before. Google Maps is also the fastest and the most accessible app for me to use. I already have an app that lets me look at the bus schedules of nearby stops to see if a bus is on time or late, but I cannot use that to find my way if I'm not sure where I'm going. Nothing has beaten the route aggregation of Google Maps for me.