I believe that plumped ores, coupled with less powerful enchanting abilities would lead to more clan/Faction styled PvP.
Going out onto the streets alone with a set of Protection II Diamond Armor would be a stupid idea, because 3 decent fighters running around in Iron have a decent chance of taking you down. As a result, players would be more inclined to roam in packs. Once we eventually die, we can go mining for a few minutes, stumble upon a branch of Diamond, make a suit, grab a sword, get food, pearls, pots and jump back onto the roads; however most players simply don't want to do this. Why?
Because most of us are terrible at finding Diamonds. Plumped ores would give us a much better chance of actually getting any Dia in the first place.
It'd be nice to try out a revision with less powerful enchants, especially considering we're trying to make some drastic changes at this point. Weapons/armor enchants would need to be toned down a few notches, such as Sharpness III being a top-tier enchant for swords, Protection II being top-tier for armor, etc.
What I would hate to see, however, is the nerfing of tools such as Pickaxes, Shovels etc. If anything, I actually wouldn't mind them being a little more powerful.
Fortune IV enchantments on picks would surely mean more Diamonds, which in turn leads to more suits/swords, which then leads to PvP. Personally, I see a lot of people saying that they have one godsword but they're too afraid to bust it out - the same goes for suits. The reason there's such a small amount of PvP is because there aren't enough people with decent gear to use in the first place. For the people in that situation, it's suicidal to go up against a pro with 10+ suits of Diamond Armor at their disposal. From my eyes, ore plumping is a great way to fix this - bringing in one of your suits is always better than fighting in your only suit.
In regards to the maps themselves, I really think we should encourage players to explore the Amplified zone at the edges of the world. This doesn't mean everyone running off to the border, setting up a lavish 1x1 hole in the dirt and never returning to civilization, but rather people having a reason to venture to the Amplified biomes, spending a bit of time there and then returning to base.
One way to go about this springs to mind:
Plumped Mob Spawning:
The reason for this is fairly obvious. It's actually become very rare to run into a Cow on the Survival server, which isn't really a good thing. Some days, I see people in chat jumping for joy about finding a Pig.
A good way to resolve this is to try and set the passive Mob spawning rate many notches up in Amplified biome - that'd kill two birds with one stone should people be inclined to go to the world-border.