Guild Wars 2

Here is my suggesting for your first foray into raid design:

Take an existing dungeon and redesign it so that all 3 paths must be completed at the same time.

For example, upon entering the dungeon the raid splits up because completing checkpoint A in path 1 opens the door to advance in path 2, while killing the boss in path 2 opens the door to advance in path 3. Additionally, path 2 players can help path 3 players in mini boss fight X by activating environment nodes on their path during the fight (which they can see below them, for example). Finally, all three groups meet up at the final boss where they need to take turns cycling into the fray, out of the fray, and running some environment nodes. It would help the level design to make one of the paths reward ranged players, one of the paths reward melee players, and one of the paths reward support players, and the final boss rewarding all three types.

This would be a relatively simple raid (a starter raid) that would allow new players to get the hang of teamwork timing and would also give experienced players something new to do while you build some full scale raids.

been there and done that….here check out my link
https://forum-en.gw2archive.eu/forum/game/suggestions/Dynamic-level-adjustment-Dungeons/first#post1448415

also later on another person with similar idea….
https://forum-en.gw2archive.eu/forum/game/suggestions/Public-Dungeons/first#post1265812