This thread is for a compilation of all the suggestions I have seen that are more for the upgrading of this game rather than personal wants or complaints. However, I will at least make sections for balance issues and will gladly change this post to reflect new ideas! If any of the suggestions here seem familiar, it's because I am taking content from your post. Be happy, cause devs look at posts like this more than individual posts, mainly because compilations get more replies and views. This thread is being revived, as I had an account switch.

Content:
*Items to create weapon particle effects
*Guild tabards and other guild gear (crests for shields??)
*The achievements are mostly lame. 10 swords? Depositing 1 mineral? Almost all of them are easily achievable with nil effort, which takes away from them being achievements. Make more difficult ones, and make the ones there more difficult. Instead of 10 swords, you should make it ten 3-star or five 5-star swords. Things like that go a long way in making a player feel they have accomplished something.
*More Quests with rewards
*Expansion beyond the clockworks, maybe to the surface for areas would be neat
*Alternate paths within any given level to other parts of the cogwheel, as opposed to waiting at the gate at the end of each level.
*More types of trinkets!
*Mini-bosses
*Chance of seeing rare content such as special treasure or mobs in dungeons (Not counting Challenge rooms or love puppies here)
*More options in the Advanced Training Hall, such as different mobs for testing damage and stuff or..
*Simulation Room http://forums.spiralknights.com/en/node/22328
*Plushies & Action Figures
*A vendor in the Main Square of Haven for selling random loot
*New Achievement! (Weapon of Grass Destruction) Awarded for cutting down 100,000 bushes.
*Houses!
*Mist Tanks that are purchasable with Tokens from Brinks . Maybe like 10-15 tokens per tank?
*More weapon types
*Mini-games for bits of CE
*Larger variety of charge attacks, such as ones that look like Giant Lichen Colony spiky ground attack and Retrodes beam attack.
*Have certain sets of achievements unlock costumes or other rewards after they are completed.
*Community Levels Editor http://forums.spiralknights.com/en/node/15965
*Craftable Vials http://forums.spiralknights.com/en/node/21490
*Allow the ability to upgrade other people equipment through a temporary trade window at the alchemy machines. This might be unbalancing with recipes, perhaps.
*More Bosses!

PvP:
*Dueling
*Promotions for Blast Network & Lockdown

UI Settings:
*Allow options to add preference for language havens
*Russian Haven
*Last known login date for a user, for guilds and friend lists.
*Having the ability to have other chat boxes for tells and other filters would be good.
*Guild Message of the Day
*Ability to arrange arsenal tabs in the order you want, for better organization
*Ability to set number of items through trade manually, instead of clicking like mad.
*Ignored people should not be able to group together

Guild Hall:
http://forums.spiralknights.com/en/node/2538
http://forums.spiralknights.com/en/node/15207

Auction House:
*Auction House should have filters
*If a person has bid on an item, they should be able to buyout the item pro-rated for what they bid on it, so they definitely will have crowns for it.
*Preview Option for items
*Allow clearing of the old auctions under "My Bids" tab

Graphics:
*Environment objects can block the sight of character from the player. However, is this intentional?
*Costume Slot for Shields!
*Perhaps some camera angle adjustments
*Thrown potions are just icons, can we have actual 3d potions? PLEASE…!
*Option to change personal color for CE or crowns
*Weapon Charge Colors http://forums.spiralknights.com/en/node/10950
*More female-like graphics for armors

Other Balances:
*Mecha Knights are not worth the 5 energy used to make them work.
*Treasure Vault Improvement http://forums.spiralknights.com/en/node/19233
*Blast Network Balancing http://forums.spiralknights.com/en/node/22500

Sound:
*Sound effect for when gates switch inside the Clockworks, so that if someone is waiting for a gate to switch and they walk away from their computer, they can hear the gate switch back.

Bugs:
Thread with various: http://forums.spiralknights.com/en/node/15678

Forums:
The Bazaar Forum needs subforums for different items: Weapons, Shields, Armor, Accessories and Miscellaneous

Threads with Various Ideas
*Achievements & Snipes Ideas http://forums.spiralknights.com/en/node/15506
*Various Ideas http://forums.spiralknights.com/en/node/15286
*Bigger List http://forums.spiralknights.com/en/node/17716
*Turrets http://forums.spiralknights.com/en/node/32125
*Ironclaw http://forums.spiralknights.com/en/node/32422
*Shadow Distortions http://forums.spiralknights.com/en/node/30645
*Devilite Boss http://forums.spiralknights.com/en/node/22720
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My Balance Compilation Thread: http://forums.spiralknights.com/en/node/27538