I sorta hate that legendarys have a certain number of standard affix types guaranteed to roll.
It bugs me that Skorn can have crit dmg, OS guaranteed, +2 chances at Lifesteal, whereas IK Mace is hampered by having no durability loss as a gauranteed stat. In fact, IK mace has only 1 random affix and a random skill mod (choose from 4). And so by design it can't even compete with Skorn. That's just not interesting, its irritating as heck.
I would rather see it that Skorn and IK Mace both have more random affixes, but yet each have a unique cool affix that gives the weapon their identity (Sorta like Windforce with knockback, or Hellrack with an extra arrow, Calamity with Mark of Death, etc).
By design I'd like to see these weapons in theory be able to roll the same affixes only differed by the unique legendary affix of each.
That goes for other item slots as well. I can't stand that certain lengendarys can roll a standard affix type that the item slot generally can't roll. Lacuni's is an excellent example. I hate that it adds movement speed, that other bracers can't have. It should roll random bracer affixes + the legendary affix(s).
For example instead of adding 12% movement speed and contributing to the max run speed, it should add something to your class's movement skills or passives. For Barbs it would add maybe 5% to sprint speed, or to DH adds 5 yards to Vault, or to Monk, a couple% to the run speed passive. That way you can have 24% run speed + what these bracers add that allows you to go above the max run speed (25%). That would be a heck of a lot more interesting legendary.
And so by doing that maybe that makes people think they are forced in to having run speed on boots as an affix, but what you should do it just open up a couple other item slots to be able to roll run speed from a random affix, that way people have choice.
In summary I guess i'd like to preserve the randomness of affixes that are rolled on rares on to legendary items, if rares aren't going to be competitive as end game gear. I'd like to have a majority of legendary items of a given item type, be theoretically equal in potential power, save whatever the cool unique affix(es) of a legendary do. Don't use guaranteed standard affixes (CD, OS, MS) as the cool unique affix for the legendary.