Many thanks for your feedback, which I will take on board. There are several initiatives we are working to address some of those things, such as the alternative routes functionality my colleague announced recently.
Being able to specify an interchange station is an interesting idea, which we explored today. There are some situations we would need to consider, such as what would happen if there is no reasonable journey that interchanges at that station, or what would happen if you specified a station that is on the direct route.
Your suggestion of the ability to only return journeys that can be taken with a Freedom Pass is a good one. Looking through the archives, I see that this was worked on extensively in 2007, and was revisited in 2015 and 2016. It seems like there were significant challenges to making such a feature available, which is why it wasn’t released. I can’t promise anything, but I am trying to see if there is any way we can provide this functionality.