As someone who ran the largest team of players actually completing the Jackal objectives and winning the map - Jackal was an amazing idea, and decently executed. Episodic content is definately where you want to go if you want to make money in wurm. I've been playing wurm for 13 years and that was the first sign of something really new and exciting in wurm. Jackal was able to take a team of people and have them committed to the overall goal, and that kept deeds together, because it wasn't about petty freedom drama - just about completing the maps objective and focusing on that, that does wonders for playerbase retention. Jackal saw a sharp decline because those players who didnt mind losing their houses didnt get a decent skillgain or reward back from investing time in Jackal previously. The skins from Jackal points? cmon... they're so boring they were insulting.
Two things you need to fix to make jackal better. Use freedom skill gain (not epics system), and have ticks transfer back to main characters. Who cares if people get more skill on their main char while working on one that will get deleted? Just make people feel like their time is well spent.
Reduce the damn slope of the spikey terrain, everyone agrees it was infuriating, even with wetas. Just cut the max slope of the jagged terrain by like 5-10.
Change those two things, and you can have a 3 month cycling server that will keep people totally entertained for a long time. I think the "heap of work" is just a cop-out. GM's and Enki mainly probably had a blast with the stronghold at the end. It wasn't anything fancy, but when we had 30-40 warriors in local all fighting back the hoards, it built such a wonderful community with players that don't normally play together. Friendships made on jackal are everlasting.
You can keep the same Jackal map even if it's alot of work, just change the stronghold location.
Thats something you can never do with Freedom in a decent amount of time.
Jackal gave that "new start" feeling while still keeping your old character.