Let's fix some of the current minigames we have to scale a bit better with level instead of adding new ones. They did a great job with Goblins, what about Survival, Course of Terror? Same with the "I want to Survive" and "Call of the Horns" minigames from the Drill Grounds. While I understand they're mini-games and not supposed to be hugely challenging, having some element of challenge would be nice.
Same with gear drops from the packs you get from Siege War. they're stuck on Level 50. Why not beef them up with level 70+ gear, or make them scale with your current class level. Open a package when you're level 80, you get level 80 gear. Open them when you're 40, you get level 40 gear. Have a chance of pulling two good green stats or one decent yellow one from the gear instead of one crappy one (having a small chance to pull a bag stat, anyone?).
Let's not add new minigames. As Cammo mentioned, there are so many it's time consuming and prohibitively expensive to run them all. We just got a new one with the Snowflake festival, if you didn't notice anyway, go run that one for a while.