Okay, i am all in for blockchain pruning or similar techniques which save bandwith and increase the overall speed.

Have you heard of the idea of a finite blockchain?
As we have all our accounts online, it should be more easy to implement than for bitcoin.

The basic idea is to have a "prove chain" which is basically just a chain of hashes containing hashes of earlier blocks. This way, not the whole blocks need to be saved but only to small hashes.
Full blocks are only kept for a short time.