New global event: Largest field competition (in each country)
Now that regular linking under a field (up to 500m) has been normalized, we can introduce global events in which agents under a field can NOT link under a field for a limited time(reverse matryoshka). During this time, factions will need to compete within their respective country to achieve the largest single field by area. Also, there can be a metric for largest area coverage within a country within the timeframe as well based on all fields in play. Fields crossing large bodies of water out of the country (standard international water borders apply) or into bordering countries would not count.
This will encourage BAFs to be built, but both factions will need to be working towards this at the same time, instead of one faction slowly building a BAF over months.