I kinda envision it OSRS gold being shaped a bit like an eye with each group using a base having a unique exit to each of the two main lanes that curve around the map making an oval. Subsequently the center is between the two lanes. There could be some negative rooms as well or branches away from the main paths too.
But a team vs team minigame similar to SC like that would be great. Nevertheless, my ideal minigame is probably of. Team vs Team minigames like Castle Wars can be fun, which is the reason one that starts everyone with nothing like SC could be good to see. When you have a fantastic team, but team coop minigames such as BA can always be great. Something for groups however, like the gauntlet could be cool if you could work in some role system in like BA.
I like the teams facet. However, most RS minigames that require teams have turnouts. It would be great to have pvp but have nothing from beyond the minigame itself affect it. Deception involved also. I'd need to invest more time thinking specifically of a mechanic that is great.
To make it successful I would say have a reward shop with some gear reward that may influence both outside of gameplay or combat or skilling but requires one to play more matches. Perhaps have every team divide. 1 person become their"champion". The remainder of the team is divided into groups to gather craft armor and supplies for the champion and the winner must increase their combat levels.
It would be a pvp minigame in Rsgoldfast which you pick your loadout from a store before it begins. The cost for every single product is randomized before the match. Every time you receive advance and a kill in the tourny you get points to spend in the shop.