I think your right instead of a casino maybe it would be better just to have more mini games strewn out around graal. Like the archery mini game in onnet town or ctf. heres a few more mini games/events i came up with:
*drasaline racing- compete in a head to head race with an npc or beat the clock by pushing the action button to go faster or to jump like the R & J event.
*bombsticle course- dodge arrows, sliding spikes, ect. while being chased by a baddie and you have to carry a bomb that you have to drop in something get hit drop the bomb and start over all within a time limit 5 successful drops in the time limit get a bomb bag that lets you carry 25 more bombs get 10 and get a hat.
*Dig- just like in the zelda games you have to have the shovel u pay a npc to start its in a fenced off area and you have a time limit to dig and unearth gralats or you might dig up a bomb and take damage
*Bomber sumo- event for 50-75 ppl dodge bombs falling from the sky and pick them up before they explode and throw them at the other players to damage them. they get eliminated if they get knocked off the platform or run out of life points. no swords. would be quick and chaotic
*joust- for 50 players each player is on a basic horse and you run around attacking each other with your sword last person alive wins
*shot in the dark- 20-40 players in a dimly lit room shoot each other with arrows last person alive wins
*tug o war- for 32-players start with 2 teams of 16 similar to team fort place a statue in middle of room grab and drag the statue across the line first time to do this moves on to next round keep doing this and splitting the teams from 16,8,4 you can attack the opposing team with your sword.
*pick your poison- event for 60 ppl there is 5 warpers to choose from only 12 ppl allowed in each warper. 4 warpers send you out 1 warper sends you to next round. round 2 there are 4 warpers 3 ppl per warper 2 sends you out 2 sends you to round 3.
round 3 there are 3 warpers 2 ppl per warper 2 sends you out 1 sends you to round 4.
round 4 there are 2 warpers 1 ppl per warper 1 sends you out 1 sends you to winners box.