One game I like is DDO (dungeons and dragons online)--in that model, the DEVs code new dungeons, and the players buy the dungeon on release with prem currency or $, at which point you get the dungeon permanently to run (1000 times or forever). The game gets $ and the players get new content.

I notice the $ method here is to add events, then add buildings and items in the events, then hope that players buy the event items instead of grinding or playing for them. All of that I think is fine, but it's only one revenue stream.

What if the DEVs made some new adventure packs (arcs of 3-5 new adventures), and just charged 1000-3000 gems for them? At least then you'd have more $ and fuel more content at the same time. You could even have the initial adventure in the pack be free to tease us to buy the pack.

Also, new adventure packs could focus on the New Player Experience with packs suitable to explain game mechanics, supplement the low level adventures, or have packs with higher level content. Packs for players 60-70 would specifically target the "end game" player who might be flush with resources, have done everything 100 times, and be willing to pay for new adventures.

Here are some ideas for new adventures.

1) Jolly Green Giant story arc, leading to the beanstalk, the cloud castle, and a new general named "Jack the Giant Slayer" with a bonus vs giants.

2) Pirate maze where the generals are on ships, the map is all water, and some of the fights are ship to ship like deck combat, and other fights use ur cannons on the ship as bonus damage. End boss could be a kraken or a dragon. End item could be the "Golden Fleece".

3) Haunted caverns with monsters to fit--all army sizes are reduced by 75% so it's more ur general and a few trained troops. Give us the real dungeon feel!

Anyway, I wanted to suggest another way for the DEVs to make $ and also produce more content.