I agree with Guildhests being practice sessions and exposure towards new mechanics.

However, the guildhests are queued and have rewards, and you're doing it with other players.

What i was suggesting was sort of an instance you go in alone, with several other NPC's that are your allies. They perform a set of action and players will have objectives similar to a normal dungeon role. These instances will only be a short while and no rewards. The difference between these instances and guildhests are not just queues and in terms of rewards but also in terms of more controlled environment. Players need to perform a set of action (pertaining to their role) effectively and they will succeed it.

While I was thinking on this, I was remembering a Sastasha run where the tank has no idea what to do. Even if he has done a guildhest before (I thought there was a mandatory quest for it?) he still doesn't know what to do and how to do it. Therefore, I thought instead of letting him dive right into a fray and maybe letting other people die (making them angry, mad, frustrated), maybe let him run a "practice instance" first where there are guides on how to do this and that.

Now I know that some people rather just teach people how to do it (like I did to that Tank, from the basic to the advanced), but in my experience, first timers in Sastasha practically don't know what to do except hit the monster with your stick. Class quests are just for one time execution, and guildhests can be repeated again and again but requires other players which can lead to external factors impacting a different situation every time it is done.

I was just suggesting a guide of step by step execution of roles in dungeons. Holding hands if you want to call it that. These runs are practically OPTIONAL and the only goal was to teach the players the BASIC jobs of a role.

It's just a suggestion.