You already know why things are they way they are. The itemisation has always been a combination of A and some of B. A lot of the time you’ll have a weapon that fits perfectly but has a bonus you probably couldn’t care for.
I still find Stonefist Rebuke to be competitive against some of the level 75 legendaries but if it bothers you “that much” just create Leviathan. It offers %bonuses to cold which you don’t have to use. etc etc.
Similarly Reaver’s Claw is fine as is. The bonuses to ring of steel shouldn’t impact your build. I would probably take Earthsplitter anyway regardless of wether I went forcewave or not. But then again I’m the type of player that has used a “Primal Instinct” relic on a Pyromancer and a “Warpfire” on a Saboteur.
I also don’t have that much issue with Earthsplitter or Rever’s Claw except that they’re your only option with a physical 1H build and the same with the 2H’ers. Yes I guess you can use a level 50 weapon at 75 but far less popular builds have multiple options to choose from at 75 and physical builds really have far too few itemization wise but multiple builds that require them (i.e. Devouring Swarm has 6 legendaries to support it and nobody takes that skill yet I can’t find a physical based 2H’er at 75?).