one thing I've wondered is whether or not Berkshire would be helped or hurt from a regulatory standpoint if BNSF / BE floated 10% public stakes, which would put a market value on them.
the conventional wisdom would be that a 10% float stock would trade at a discount to peers, though I'm not sure that's the case as the float would be big enough to attract a liquid diversified but high quality shareholder base (10% of BNSF would be a $12-$16B company), you could probably build a decent shareholder register quite easily, and the governance concerns with a minority stub, in my view would be mitigated by the berkshire brand / very understandable capital allocation policies (BNSF distributes cash as it can, BE retains earnigns)
would the market look on Berkshire differently if instead of owning these 2 businesses privately (worth about $200B in my view: UNP + 2x book for BE = $200B, $150B if you're feeling conservative and value-y) Berkshire owned 90% of them and 10% floated freely. they are already SEC filers with independent capital raising ability.
tax consolidation would still exist above 80% ownership IIRC.
would Berkshire as a business benefit from this?