Bitcoin is a very well known technology. But its infrastructure is still not sufficiently developed.
What do you think is the most important direction for bitcoin development now?
The area I think development is needed now is on the issue of synchronisation in the area that, an individual having an account on BTC.com. Blockchain.info, Xapo, Paxful, and other wallet providers but no one can see that or he has to download all of this providers app in other to keep his funds safe. Another is the issue of fees of some wallet providers which is fixed and not making room for the volatility in price accordingly.
If I got your post correct, then I would say there isn't any need to have a synchronization between various wallets. Why would you want to have synchronization between different wallets with different private keys. You can very well import your private keys in other wallets. What all you need to do is to opt for those wallets which give the option of owning and importing your private keys.
If you meant something else, please explain your point more as it is little ambiguous.