I don't see why a chain split is to be avoided ; I would say, on the contrary: the more it splits, the more different versions can compete in the market, and the better the outcome will be. [...]
In fact, in a certain way, alt coins do that already, but I think that it would be better, instead of starting new chains all the time, to fork off from existing ones, to have initial distributions which mean something. After all, to get something going, it is much better to hand it out to a large existing audience than to try to win a new audience.
I disagree somewhat. A chain split would mean a severe usability reduction. Every user that uses a certain number of Bitcoin services (e.g. exchanges, merchant sites, remittance services)
is deprived from using a part of them in the case of a chain split if he doesn't want to use both chains. And using both chains is also a severe usability hassle (even if there were "multichain" clients).
I don't see why. After all, a chain split doesn't "halve" the users or the coins: the old chain remains exactly as it was, with all the holdings etc... and all its functionality, and all its users. Of course, if the old chain loses traction, then of course, it will lose out to the new chain - but I don't see the difference with an alt coin.
In fact, the ONLY difference between a new alt coin (with a fresh genesis block) and a (bilateral) hard fork, is the initial distribution of the new coin. With a new genesis block, this distribution "starts from scratch", which could be a pre-mine with or without ICO, a new eco system of miners/minters etc... and the slow building up, or not, of an eco system, which takes time, which can go wrong etc...
With a hard fork, you take as an initial distribution, the actual bitcoin distribution at the moment of forking. In fact, technically, you could even start a new genesis block and take as an initial pre-mine in that block, all the UTXO on the bitcoin block chain at a given block height, instead of forking off from a given block and keeping the old, messy chain dangling there.
For instance, in the proposal to change bitcoin to a PoS coin, or to change the PoW of bitcoin, it could just as well be done that way: a new genesis block, that is (verifiably) the UTXO of the bitcoin block chain at a certain height (one could even leave out Satoshi's stash for instance, so that this burden is gone) ; this is equivalent to forking off at a given block and forbidding Satoshi's addresses, but it would technically be much cleaner.
Usage is what actually gives value to cryptocurrencies - without usage, they would be simply a software with no real use cases, because "low-to-zero" valued blockchains are easily attackable and wouldn't even usable as a Factom-style "notary" ledger.
Well, I'm absolutely convinced that the market prices of coins have *strictly* nothing to do with any form of usage, but are purely speculative. Under any realistic estimation, the demand of bitcoin for usage (buying stuff with, apart from buying alt coins or fiat) should result in a bitcoin price of, say, $20,- to $100,- at this moment (I can explain this with Fisher's formula). Most alt coins should be very close to a few tens of cents at best. I have a less good view on ethereum, if one considers "gambling" a genuine buying of stuff.
So my stance is that alt-chains are a cleaner way to experiment with different implementations. If you are worried about the distribution of the supply, then your alt-chain can simply use a snapshot from the Bitcoin balances at a certain block (like "BTX" and "CLAMS" have done).
Yes, but that is exactly what a fork is (see above). There's no difference in principle between a compacted new genesis block with a coinbase that gives the bitcoin owners their original holdings in the new coin, and a "clumsy genesis block" which is a 140 GB piece of block chain. Everybody can go and check that the coinbase of the fork is "right" ; it is simply a more compact form of the information that is used for the new coin from the 140 GB bitcoin chain up to the splitting point.
A fork is an alt coin with the same coin distribution at the point of forking than the original coin.
If the fork wins in the market, or if the miners abandon the old coin, then there is some psychological effect that calls the "only continuation of property" which is the new coin, the name of the old coin. If both continue to exist, there is no fundamental difference between an alt coin and a fork, apart from the initial distribution of coins.
That's also why I support the agreement and only would support UASF in the case it has a real chance to get a supermajority of miners, exchanges/economy and users.
But if that is the case, no UASF is necessary because the Core stuff would activate.