Interesting - but it's a development kit, not a working controller. If you're into hardware as well as software and don't mind spending lots of time just getting the thing to work reliably, fine. I don't think that's what 'dc-bikes' quite has in mind.
There's lots of guidance, and a huge amount of work has gone into finding sources of critical components, and if I had a bike with a duff controller I couldn't replace I'd certainly be tempted to try a 'roll-your-own' but it's not something for someone who just does a bit of programming to tackle. Also I note that the development kits are likely to need some modifications themselves to deal with the sort of current an e-bike motor might need. 48 volts at 10 amps is not a conservative enough rating for this application.
Serious money too, I expect. I don't see any prices quoted.
Rog.