- we'd avoid causing clones, which reduce the trustworthiness of the altcoin phenomenon
Whatever the other merits of your approach, this one is silly. There are hundreds of altcoin clones, with countless more released every single day. Whether or not your particular pet coin gets cloned or not makes no difference at all to the overall phenomenon.
You say that like its a good thing. Whether or not you agree with XC only open sourcing the previous version or not the hundreds of clones/scams/p&ds being released on a daily basis is greatly damaging to the altcoin world.