They could do a bracket type Atlas Island where teams are put into 8 team groups by APR.
So teams 1-8 would be on an Island and each team would fight in week 1 (1vs8) (2vs7) for a castle connected to their starting castle. The Winners would then fight the next week and the losers would fight. Same for final week. The Champion of the Round would get Awesome bonuses and then lesser bonuses down to the eighth place finisher. This would give EVERYONE regardless of alliance targets to hit and would last 6 weeks so 2 of these could run per season. Just an idea (better than more castles) that would allow strength on strength and balanced competition. Teams would be shuffled based on APR (which calculations could be updated and improved for sure) every 6 weeks. Every week there would be someone different to fight. I would also double revives, make troop loss only 10% regardless and give bullhorns instead of rubies and lame prizes for good defense. Have wave attack times where teams can block out periods of the day where the castle can not be attacked (stole that one) and then it can be like a massive fight. If only losing 10% and being able to revive faster even smaller troop teams will be able to fight. I realize fighting with an alliance or 5TA might sound weird but with the decreased troop penalty it would be more like swapping. But it would be fun competing against someone your level!
Could also be expanded to 64 teams APR 1-64 for 6 weeks but I do think there is a bigger difference between 1 and 64 than 201 and 264.