Guild Wars 2

simulator room (customizable sand box)

choose from a number of mini maps or just plain rooms of different sizes
choose from a large number of props to place in the room
choose from a number of functional environmental things (switches, platform booster, capture-able sentries, etc) to use in the room
choose from a number of objectives or combination of objectives
choose from a large number of different or same foes to combat (possibly multiple copies of bosses, champs, regular foes, or any other not mentioned foe type(some limits may be place to prevent exceeding limits of game engine). Each foe is worth a certain amount of points when defeated, depending on their difficulty. End of simulation tabulates total won and loss (undefeated counts negative) (possibly from a time constraint limit option) and balances out to total out a final score.
different high scores or combination of any of the above choices may lead to different awards or unlocks or secret levels, or secret prizes (may not stay secret that long though…), or anything for that matter. completing secret things may lead to revealing of other secret things that can be obtained and so on.
Essentially you create your own game to test the limits of one or a group of players (and possibly create new gameplay or content)
This room will have five room saves to use or repeat if necessary (maybe more).
simulator room allows players to create their own end game and possibly create their own game within the confinements of the simulator room. this room may contain things and objects not normally found in the normal game (like different robot types, mounts, prototype things, commando profession, stick figure people, any number of things, FPS weapons, RTS type buildings with soldier unit production…)
add more additions as needed.
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other suggestions.

have mini waypoints right next to each npcs (merchants etc) so that you don’t have to go to a waypoint and can go directly to any npc.

single click on npcs (bankers, merchants, repair anvils, etc) auto opens what they have or do, instead of double clicking on them(talking to them could be done afterwards).

have floating seats for spectators to sit down in and watch the fight from above.

speed up illusion move speed when shattering.

many skills have too high of a cooldown time to be effective in spvp.

You need to divide your suggestions up into different threads. But most of this isn’t in the realm of possibility. Except to some extent with guild halls. That’s assuming this isn’t a troll post I’m not sure. Good luck either way. Trolling is fun.