Pardon me for being so frank, but you are significantly overblowing this.
First, please take a look at the
cumulative experience table and this
plot of the per-level line. Next, allow me to direct your eyes to the
Mining experience table that I created and verified myself. (The other experience tables were copied from the MCMMO wikia and don't reflect the changes made to the plugin by MineTown devs.) It only takes a little mental math to figure out that with values like those, it will take a LONG time to gain a significant benefit from the passive skills. So to your specific concerns..
Mining Anecdotally: during the week or so we had MCMMO recently, my mining skill got to about 100. I was not exclusively mining, but I also play quite a lot. Using that rough estimate, the 25% double drop chance you're so worried about would take a month's worth of work if not more. A 50% chance, 15 weeks of play, and much beyond that you start talking about
a year of regular play. In my opinion if you stick around long enough to actually reach the ~11 million experience required to max out Mining, you deserve the perk of having everything you mine double up.
Also, why are you even worried about double drops ruining the economy? Fortune picks already let you get up to
four times the item drops from coal, lapis, redstone, and diamond ores. MCMMO's double drops would apply to other block types, yes, but because you cannot turn off the passive ability all that would really result in is a lot of extra cobblestone and netherrack being ignored. Iron ore is already so plentiful that it really wouldn't matter, and gold is the same way because of the bank currency converter. In fact, it could be argued that the slight amount of extra (generated) blocks would gradually drive down the cost of building materials and benefit the players who like to build more than they like to mine.
Blast mining just makes it slightly more efficient to use TNT for mining. I don't think it's important so that's all I will say about it.
Excavation (For the record, Excavation applies to five blocks: Grass, Dirt, Gravel, Sand, and Clay Block.)
You say you're worried about the chance to find diamonds when you're digging, but it's a 0.13% chance and I'm not sure you have enough perspective on just how small that is. A plain diamond shovel has 1562 uses.
This is the distribution of diamond drops after using an entire diamond shovel. In fact, generously assuming a
truly random number generator, over an entire double chest of blocks (64 × 9 × 3 × 2, or 3,456) you will average four to six diamonds. In reality they will probably be much rarer than that. I would be worried about the 5% cobweb and slimeball drop from clay blocks, and the 1.33% cocoa bean drop from grass and dirt, before I would worry about 0.13% diamonds.
Unarmed Berserk increases Unarmed damage by 50% and enables Grass, Sand, and Gravel to be broken instantly for the duration.
Yes, a successful Disarm makes the target drop their weapon. Yes it is just you, the skill is not a terrible idea. Aside from extending the gathering aspects of Minecraft, MCMMO also adds another layer of tactics to PVP combat.
- Unarmed has Disarm, letting you get an advantage over someone too reliant on their weapon.
- Swords have Bleeding that provides Damage-over-Time to discourage fleeing from fights.
- Archery has the Daze passive (makes target unable to move and stare straight up/down for its duration) and Ignition (more DoT). It's important to note that dodging or blocking an arrow cancels any additional effects.
- Axes have Critical Strike to do ridiculous damage and end fights more quickly.