All what I thought of would work, but I wanted something more elegant, less restricting and more encouraging, and after two days of intensive thinking the Muse of Gaming paid me a visit :) What if I had a period of time within which a player has to capture a Soul Gem or there would be some unpleasant consequences? I liked the idea right away, just needed to put a bit more thinking into it and figure out what kind of a timer it is and what consequences are, to hit the golden middle of not being too pushy, but still encourage people to advance further – and that's how the Astral Countdown emerged into the World of Undecima.
The Astral Countdown will start ticking after a Town Class is researched for all new players (no point of restricting newbies) or on the next login for all existing players (if they have researched a Town Class already). I even thought of a little story behind it and here how it goes:
"You have researched a Town Class and now your Town is bound to the World of Undecima. To keep developing your Town, you will need to capture more Soul Gems. The Time is ticking away and you can see your Astral Countdown in your Keep - by the end of this countdown, you have to capture one Soul Gem. If you fail to do it, you won't be able to do any upgrades or researches in your town and you won't be able to attack other players (unless they attack you first) until you do capture a Soul Gem.
With the steel of Might, the power of Magic, the spirit of Nature, or the light of Faith, prove that you are the worthy one."
As I'm writing this post, the Astral Countdown has been implemented already and so far the response was good, even from the people this new feature was supposed to affect the worse (those big fat sitters who didn't want to advance further). There are some exceptions for people being attacked and for people returning back to the game after some prolonged absence as well. It's been running for a few days only and as the time goes, it may need to be changed and adjusted more, but all in all, the mission is accomplished and we'll see about the results later.