Something like the sims or sims medieval, or a mixture of both could work very well for playmobil too.
They'd probably need to remove evolving families, aging and all that though, no need for clicky romance to go further than hugging and kissing.
Just being able to put your own house together from playmobil parts, put clickies in it and give them a job could work. they could walk around town, make friends, buy things, and each job could give different gameplay. Work hours could be anytime during the day unless its a night job.