I am coming back on this subject.
If you are writing the business manager, that would be better to give the ability to add a new source for a new SEPA account as it's impossible to do it now on STRIPE dashboard.
For instance on the front end, may be give the customers/mods a feature to change a default source or add new ones for STRIPE ?
That's not good for customers to be obliged to have their subscription cancelled and renewed with only new banking coordinates.
It's not something trivial to implement, as it requires some changes in both core CBSubs and CBSubs Stripe gateway. So it won't happen "soon" (thus no ETA).
No worries, we deal for now from STRIPE to cancel subscriptions and re do them manually from CBsubs with the moderators as it's the only solution available.
We intend to stay with CBSubs even if there are some small issues to deal with for our business, as the solidity, the adaptation and scalability of your solution outperform a lot these issues