Well, as long as noone conclusively wins outright, we will have a standoff that will leave Miners on Legacy Chain very much obliged to slowly move towards UASF chain with the growing risk of reorg.
Doubtful. I would expect that the legacy chain will leave the UASF chain in the dust, with no hope of ever coming close to such reorg. Even if it did, however, there are trivial means to ensure such a reorg does not occur (e.g., invalidateblock).
I am not so sure. UASF only needs 51% minus the share of the biggest pool. If this pool is as big as it is said, then they need very little for all the other miners to have a clear incentive to move and not run the risk of being moved on.
I hope it fails, because of how it was handled. But I do not think it is farfetched.
I think you missed my point. All any given node has to do to avoid a reorg is to invoke invalidateblock for some block uniquely on the chain he wishes not to be reorged by. If a node that is following the legacy chain invokes invalidate block for a block uniquely on the UASF chain -- perhaps the first uniquely UASF block -- then that node will never be reorged by the UASF chain.
Of course, it may be that not all legacy nodes will invoke invalidateblock upon a uniquely UASF block. But all that do are protected from reorg. So it would depend upon incentives. Who might have an incentive to avoid such a reorg? How about
every freeking node owner that prefers legacy over UASF. So it is likely that the overwhelming majority of nodes that do not adopt UASF will protect themselves thusly. Further, the incentive to avoid a reorg climbs as the chain grows, as more value gets locked up in blocks that differ between the two chains. So it is likely that any laggards on the legacy chain will protect themselves thusly as time goes on.
And that is just one mechanism -- one not dependent upon the actions of others. I quite prefer Jihan's plan, whereby a new client is adopted by those not adopting the UASF that encodes that any chain lacking a larger than 1MB block is invalid. Of course, this depends on mining support for this plan. Not only to be a valid chain, but more mining power must go along with this to avoid the ability of Jihan to 51% that chain.
So no -- there will be no reorg -- at least not for anyone aware.