This is very unusual the way they set up these new skills. It would seem that once you get Bountiful Yield you can essentially ignore the newer skills you get for yield. I'm not sure if this was intended. If it is, then Bountiful Yield should really come after the older yield skills when you're leveling up. Also King's Yield I / Blessed Harvest I are technically useless.
If you just take raw numbers, it would seem Bountiful Yield is King. Sense we know we get 5 GP per hit, we can use that to figure things up. Keep in mind every hit, is one yield. And let's assume we are hitting a point that has 5 attempts, and your at 100% success rate.
Bountiful Yield takes 200 GP or 40 hits
King's Yield II /Blessed Harvest II takes 500 GP which is 100 hits.
After simply 200 hits you get:
5x Bountiful Yield activations = 25 additional materials. In total you've gotten 225 mats
2x King's Yield II/Blessed Harvest II Activations = 20 additional materials Total 220 Mats
After 1000 Hits you get:
Bountiful Yield = 1125
King's Yield II/Blessed Harvest II = 1100
Honestly when you do break it down the difference seems pretty negligible, and you also have to consider this. If I'm saving that small sliver of time by using King's Yield II/Blessed Harvest II, making up for not using Bountiful Yield? Not spending the time to do the extra activations of Bountiful Yield over time, may make up for its shortfall. Sense every extra activation of that new skill could be an actual hit instead. Perhaps I'm missing something in the description. IMHO they should of increased the yields of the old skills by one each. That way King's Yield I/Blessed Harvest I aren't useless once you get them.
This also opens up the possibility to using Unearth II + Bountiful Yield together. Something we would of only dreamed of doing with King's Yield 2/Blessed Harvest 2. Granted I haven't hit lv60 with all the new HQ/Melded gear. I'm sure even then Bountiful Yield will come out on top.
Oh ya P.S. guys we got some new skills we had no freaking idea we had, unless you paid attention to the patch notes, and went and looked in your actions/traits UI.