I have an alternative to the idea.
Maybe if a tribe was built up of twenty randomly matched online players All in the same league. A new tribe war would start every league season and each season you would play with 20 new players. The aim of it would be like a clan war but much more evenly matched. And for winning you would get bonus gems or something depending on your league (bronze 3 eg 2 gems, master eg 100 gems).

