It gets way more complicated and messy than that ... probably not many remember the GPU hashrate war that Namecoin and Bitcoin got locked into in late 2011, it was finally resolved by the release of a merge-mining client hardfork for namecoin (for the good of cryptocurrencies generally). The hashpower will jump from chain to chain depending upon which one has the best instantaneous profitability, there will be zero loyalty at all. All these advocating for a hard fork are clueless, they have no idea how mercenary the miners are due to the amounts of money they are outlaying continuously on electricity and other costs. The profitability calculations includes chain difficulty and price. So every difficulty retargeting on either chain will become an unstable lurch of hashpower from one chain to the other, with all kinds of pricing games and volatility on the markets associated to the lead up to it ... it will be ongoing and crazy volatility like out of chopstick's nightmares, day trading will become like a crazy feeding frenzy in a shark tank. If Ver is really crying about usability he would be running very, very fast away from a contentious hardfork to two competing hashpower chains, because it will definitely kill usability for months, maybe years.

Throw in the facts that you make about BU's crazy approach to replay attacks, orphaning and generally really, really unsafe extensions to chain-building (emergent consensus wtf?) then there is going to be chances whole fortunes will be wiped out if your coins move onto the wrong chain that suddenly disappears due to some crazy prize spike, an unfortunate timing for a difficulty retargeting and an attack on BUg, e.g. (reorgs).

Good luck, chumps. Enough of yous have seemed to welcome in Ver and Jihadi's version of hell to make this the new future ... welcome to the party you stupid fucking idiots, let's go back to blockchain grade school.