For people to actually wanna be apart of your map you should invite them in with text in borders or custom made pictures stating what your map has
For Example -
Heroes - Have a unique spell system that allows you to swap out between 20 spells. You can also rank your hero up allowing you to learn new spells
Terrian - you can Click on trees to cut down for woods, pick up rocks to craft, Ram a tree to build bridges, etc
Spells - Each spell has a custom system that has an arch. Players have to use the spell upon location and have a chance to miss if unit has time to move from spot. Etc...
Citys - We have huge citys that can have 100s of quest, milions of people to talk to, etc