As topic, both end game very difficult to obtain weapons (especially with good rolls) could use some small share of love.
My opinion is entirely based on personal experience playing those builds made by our top builders (and also a bit of common sense looking at the stats) - perhaps there is a valid reason why no further buffs to those weapons would be done - but at least lets have a constructive discussion.
SoulRend: falls behind Winter King, suggestion is to add some small buffs like 8-10% phy resist to SS for 3 seconds
WorldEater: The build which finds best use is a FW Fire Commando - though it is very squishy build for a melee`ish one - adding some Phy resists to the weapon would do it justice and fill in a gap in the build.