Hey! Before come with all your love for the "open world" thing, please read. o__o
Instances in this game don't need to be that kind of "easy grind" type of instance, like we can get in a lot of another korean MMORPGs.
First of All! Some global restrictions for the instances.
1. A full party.
2. One Key (I'll explain below)
3. Min AP/DP. (Optional)
4. Cooldown per account/family (same way of the World Bosses and the account restriction is optional, can be per character.)
5. Instance boss boxes can be bound to the accounts. (optional)
Each instance has a "entrance key" the item that you need to open the instance on it's door, without the key, U'll receive a message "You need "X" Key to enter inside this intance".
The key can be drop by parts. 5 parts of the same key creates the Key. (exactly the same system used on the relic shards). The Key parts can be sold on the marketplace. And need only one key per group. Or you can drop the complete key instead a part, and everyone need to have their key.
So, let's go to the examples.
Liverto Dungeon! (Balenos Region)
Battle: Need to be a HARD instance for the 130 AP / 190 DP Group but possible. Monsters with chance to drop rare itens (black stones, steel taritas, relic shards, etc) and the final boss a Liverto box.
Boss Battle: PLS! A decent boss battle with at least 2 phases and 2 group mechanics per phase.
Boss Armor Dungeon! (Mediah Region)
Boss Armor Key
Battle: Need to be a HARD instance for the 150 AP / 200 DP Group but possible. Monsters with rare chance to drop Grunil, Forbidden Book, black stones, etc. One "sub-boss" with a CHANCE to drop a Liverto Bundle and concentrated black stone or Ultimate reform stone and a RANDOM (I know that you all love RNG) Final Boss (Red Nose, Tree Spirit, Bheg, Giath, Muskan) dropping it's respective box.
Boss Battle: PLS! A decent boss battle with at least 3 phases and 3 group mechanics on the first phase, 2 group mechanics on the second phase and a final phase with all 5 mechanics .
And Also! Following this model.
Kzarka Instance with 30 hours Cooldown (this fight can be a "players vs boss" style, like the Bahamut fight on the Final Fantasy XIV.)
This fight need to have 4 or 5 phases for experienced groups, with some concentraded black stones, one ultimate reform stone and one liverto box and a CHANCE for kzarka box.
And same way of the Kzarka for Nouver and Kutum and Harpia.
Remember this is the content for ORGANIZED GROUPS or "static groups". This kind of content improve the community, create more ways to the players can create content of the game for youtube, livestreams, guides, etc.
Please give your feedback based o what's better for the game and not your own taste.
thank you. =D