You're over complicating things. If you use the bitshares blockchain at all you don't need Notes. Regardless of whether or not they attempt to merge, you will see a music platform developed on the bitshares blockchain, since both blockchains will use the same technology.
I want to allow Music stakeholders the freedom to experiment with their DAC ideas without being burdened by the rest of BTS stakeholders who may not care about their application.
Have you looked at the white paper for peer tracks and the bitshares music blockchain? There is literally no enhancement over the bitshares blockchain and there doesn't seem to be any interest in making any enhancements on chain.
I want other new innovative DACs to do AGS-style crowdfunding campaigns directly on the BitShares blockchain with BitUSD but keep the BitUSD collected in a controlled reserve that the devs cannot just freely spend as they wish. Rather there would be controls on it ultimately enforced by the shareholders of the DAC (the UIA holders).
I don't see how you plan on implementing this in a practical manner. Perhaps you can do this through a multi sig account where devs and managers of the DAC must come to a consensus on how funds should be spent, but it would be erroneous to assume that you could get substantial shareholder participation that would allow for the timely use of financial capital.
I want side chains so that experimental DAC features can be tested on their own blockchain without interfering with our flagship product (or adding extra validation burden on delegates), but I still want these DACs to be able to use our BitAssets.
I'm not saying that cross chain trading isn't a worthwhile feature. I'm merely saying that sidechain and crosschain trading aren't a necessity. Side chains and cross chain trading are not with out there complications and cost, both in terms of added expenses to maintaing the network and reduced ease of use.
Perhaps some of these features would be desirable enough to later port over to the main BitShares blockchain once they are stable, or perhaps we decide to just keep some of the features on their own side chain.
I'd be more inclined to test new features if they are on a single development chain as opposed to many chains for which I have to build or download multiple applications. Side chains/multiple chains were a long standing theoretical discussion on this forum prior to the launch of bitshares x, but in practical terms they're not as beneficial.
Perhaps BitShares Music is simple enough that is not the best example of a UIA-based side chain (although it would still work perfectly fine as one). And perhaps we would prefer to just copy its features over to the BTS blockchain. I certainly am not a fan of another merger. But in general I would like a mechanism where the separate chains can try out different experimental business rules and features without burdening the BTS blockchain and delegates. Using a completely separate chain works, but then they need to use separate BitAssets, cross-chain trading, and the liquidity and peg may not be as good as the BitAssets on the BTS chain.
The idea I've laid out here
is to allow the BitShares BitAssets be stored in the reserve for the child DAC so that the child DAC can then use a derivative of the reserve BitAssets in their own blockchain. Those BitAsset derivatives can be transferred between users using whatever fancy rules they want for the DAC without burdening the BTS parent chain with those rules and corresponding validation. In order to prevent theft of reserve funds, a small 24 hour delay is unfortunately necessary for reserve withdrawals and some other operations, and a panic mechanism is available in which a quorum of UIA stake (could be a small percentage like 5%) can halt withdrawals, and assuming it wasn't a false alarm, another quorum of UIA stake (say 50%) can vote to resolve the panic by changing the issuer of the UIA (which happens to a be multisig corresponding to the block producers in the child DAC). Cross-chain trading of the assets between chains is of course always available if someone doesn't want to wait 24 hours.
Regarding the crowdfunding, the BitUSD would be sent directly into the controlled reserve and the issuer would be authorized to print a corresponding amount of UIA to send to the donaters on a daily basis. This way the stake of the DAC slowly builds up and becomes more decentralized as the crowdfund goes on. Since the stakeholders can ultimately vote to change the issuer (who is the one authorized to make withdraw transactions that pull valuable assets out of the reserve), it means the stakeholders are ultimately in control of the funds they donated. For practical reasons there will of course be delegation of management, control, and decision making. But the idea is to not impose any policy on how this delegation is done. Each DAC can figure out its own way of doing things by building it into the blockchain rules of the child DAC. If those rules are violated, honest stakeholders are ready to press the panic button on the parent blockchain, which will halt withdrawals and other significant actions by the issuers, and then they will change the issuer to a group of people who are more honest. The stakeholders who were quick to legitimately press the panic button are financially rewarded to incentivize them to monitor the actions of the delegates/issuers; on the other hand if they cried wolf, they will be punished by the blockchain taxing part of their stake.
Side chains certainly aren't necessary. Having independent blockchains works. But if you do that you are forced to use cross-chain trading to exchange assets between the chains. The cross-chain trading can be avoided if you just put everything on one chain. But the reality is people are going to create independent chains because they want to try out something different that they cannot get approved on the main chain. My thinking is that it is better for us if we provide an option for others to build that as a child DAC on our BTS chain and have them use our BitUSD (which provides value to BTS rather than their core cryptoasset), rather than forcing them to produce a completely independent blockchain and have to go through the headache of building up their own liquid market-pegged BitCurrencies.
It also can help with developing experimental features. I know there is DevShares and I know it is also a headache to have too many chains (block producers need to be elected for each one, a client needs to be compiled for each one), but just because we have the option to have 1000 different DevShare-like child DACs doesn't mean we will. It is still nice to have the option to fork off a new DevShares (with BitUSD shared with BTS) for a group of developers to experiment with a different approach without having to compromise with or step on the toes of the developers working on the other DevShares chain.