I think it's no secret that the game - as it is today - has some problems: there are technical problems, a good number of game mechanics is still not implemented, some game mechanics are prone to exploiting and some (many?) people already ran out of things to do. Here's what I would do to "save" the game.
Might be a longish read, so be aware and no, there's no tldr version of it. Be also warned that I suggest another wipe of the database. Yes, I suggest we start over again with an altered ruleset and altered game mechanics. I believe it's inevitable because some of the current game mechanics don't work that well and I think we'll be better off facing the fact than to screw around with the current setup.
The map
I suggest to return to the map we had in beta, before the first attempt to launch the game in february. That means that all junkpiles that have been placed into the wilderness in the map-update get removed and we only have junk piles at the real-life population centres of the Lake bassin again. The main reason for this suggestion is to have to trade again: fewer tribes should be self sufficient. It's currently far too easy to have a junk pile and food and other natural resources within the land of a tribe, especially when it's one of the larger tribes with more than 20 members.
Along with this goes the restriction that no fish and no plant should be found within 50 meters of a junkpile. Let people decide whether they want junk or food but don't give them both easily. Likewise, there should not be much grass or branches near junkpiles. After all one cannot find a lush green meadow in the middle of a city.
Terraforming
I think that terraforming is one of the main culprits for the current low performance in crowded zones. I also think that terraforming in it's current form creates an ugly landscape and makes building walls from stone or barricades from wood more or less superfluous. Why build a wall from stone when I just can raise the terrain to laughable heights. Therefore the amount of terraforming in the games needs to be limited.
My first suggestion is to have a piece of road needing 10 granite bricks, that should limit the amount of roads built. Furthermore, lowering, raising and levelling terrain should be an exception and not the rule. Therefore I suggest that a shovel breaks after a set number of terraforming operations (let's try with 50?). Should make people think about where they terraform instead of just digging bottomless pits.
Crafting system
Currently there are only two crafts that don't need any junk: masonry and woodcrafting. Both of these crafts do not produce any useable item. Basketry needs a few junk items, all other crafts need copious amounts of junk to produce anything worthwhile.
This should be changed, we should have two nature-centric crafts (basketry and leatherworking are the obvious candidates) that need only few items from a junkpile and three junkpile centered crafts (weaponcraft, toolcraft and tailoring) that need only few materials found in nature. Bonecraft should be in-between the two needing both nature and junkpile materials. Woodcraft and masonry can stay as they are, architecture needs recipes that can be built without large amounts from a junk pile, for example grass huts, leather tents, wood barricades, etc.
To make this work the amount of leather and fur (what's fur good for by the way?) that can be found in junk needs to get reduced by a large number, say by 90%. Also, both masonry and architecture don't have enough meat to the craft. I would combine these two crafts into one.
The reason for these changes again are to introduce trade and to require people to travel the map in search for materials and crafters instead of having everything just 20 meters away from their totem.
Resources
As far as I know there are currently very few natural resources that are somewhat rare, I know of only three: tar, obsidian and chalk. Additionally, these resources are not in high demand.
I suggest to have at least three times the amount of rare (and/or regional) resources and to have more recipes that need those, especially when it comes to high-level recipes.
Alignment
There is currently no alignment system in Xsyon but I think that we desperately need one. Here's my suggestion:
All players start blue. Players turn red when they initiate attack on a blue player or when they are member of an evil tribe. Leaders of good or neutral tribes can determine whether they want their tribe to become evil when a member becomes red or whether they want to auto-kick the now red player from the tribe. Tribeless red players auto-switch to blue after visiting 12 different map zones (zones with only water don't count) without attacking another blue player.
PvP and laws
Difficult section because so many people have strong opinions about PvP, either for or against it. Personally I always prefer faction-based PvP but I cannot see how that could work in Xsyon. Here's my suggestion:
All land outside of tribal grounds stays FFA PvP. Tribes can have their local law that determines how PvP is handled on their tribe land. There are three settings for each tribe, depending on the tribe alignment.
For good tribes: no PvP on our land at all, red (evil) players can be attacked, FFA PvP
For neutral tribes: no PvP on our land at all, red (evil) evil players can be attacked, FFA PvP
For evil tribes: Blue (good and neutral) players can be attacked, red (evil) players can be attacked, FFA PvP
All tribes that have flagged themselves as warring tribe can be attacked by members of other warring tribes without any alignment hit and without any respect to local law.
Please note that this setup allows tribes to protect blue players on their ground, no matter whether they are member of that tribe or not. Thus if a blue player enters the land of an evil tribe he's fair game if the tribe wants it so. If a red player enters the land of a good or neutral tribe he can be fair game too, depending on the local law. If a blue player enters the land of a good or neutral tribe he can be protected if the tribe wants it so.
Enjoy ripping this piece of text apart.