I'm a proponent of implementing simple blinded transfers first and not the current privacy-leaking stealth implementation. Then much later a better design for stealth could be implemented. But even with that approach you do bring up a very good point:

Also don’t forget about the fact that if you hide your balance you won’t be able to vote afterwards. That is quite worrying especially if you wanna hide a big amount. At least Yunbi won’t be hiding it’s balance, so it will be a big blow to how people receive funding.

This is a pretty big concern. I wish there was some way to have voting without exposing the balance that is voting. The only way I have thought of requires exposing your balance to a third-party that accumulates the votes (but is cryptographically prevented from falsifying the votes). Even then there are tricky privacy leaks that are still possible.

Perhaps it makes more sense to have the voting BTS balances be public but stored in an anonymous account that is not linked to the user's normal account. But doing that right means simple blinded transfers are not enough and a better stealth implementation is needed (decentralized on-blockchain coin mixing). So in that case perhaps it makes sense to delay blinded transfers as well until a proper stealth mechanism is designed and implemented.

Finally I wanted to add a side note on sidechains. Honestly that would be even worse than adding stealth. Doom scenario for sidechains : Bitcoins worth 2M USD are held by the Bitshares Blockchain.

Yes, that is a major and potentially devastating risk for BitShares if sidechains were implemented. But there is also great benefits from sidechains, namely that our DEX would actually be decentralized from the perspective of typical cryptocurrency traders who have no interest in smartcoins. Also, you must compare it to the current situation. Right now the trust is in, for example, OpenLedger (a single entity) to not steal the BTC reserves for OPEN.BTC. Now I think OpenLedger is trustworthy, but I think it is a valuable example to use as a point of comparison to sidechains. So instead of the majority of witnesses colluding, OpenLedger would just need to decide to steal the reserves. Instead of the majority of witnesses getting hacked, only OpenLedger would need to get hacked for a hacker to steal the reserves. Decentralization through this sidechain mechanism reduces the risk.

Of course, if the multisig is not selected as a set of trusted parties but rather a dynamic set of witnesses, then a new risk is introduced which you mentioned. That is the risk that someone might compromise the big proxies (or exchanges holding huge amounts of BTS), and use that voting power to vote in their sockpuppets as witnesses for just long enough so that the control of the reserve is handed over to them according to the sidechain protocol. This is a legitimate risk, but we need to decide if it is enough of a risk to outweigh the immense benefits of sidechains.

That said, a lot of the other features you mentioned at the end are also very valuable for BitShares. And perhaps many of them should be prioritized over sidechains.