It doesn't make sense as long as people still follow the rule of "build off of whichever version of a block you see first", but if some people stop doing that then some possibilities open up.
I think this is not true.
I think the rule is: "hash on top of the longest chain (measured in work, not in blocks)".
Yes, but if two blocks are found with the same difficulty then they are considered equal work-wise (even if one has a smaller hash value-- the "Bits" field in the block is used to compute chain work, not the block hash).
If there are several valid tip-of-block-chain choices all of which have the same work, then miners are free to build off whichever one they like. The rule everybody (I think!) is using now is "build off the one seen first."