Something I've been thinking about..and might have even talked about it before :)
When the Clans first arrived, 2:1 odds were even in terms of the fluff. If you sent a Regiment (or even a RCT) the Clans hit you with a Cluster. This changed as time went on and the IS developed their technology. Now the IS is producing their own Clantech in many cases and buying a lot more, and the tech parity is there. Sure, the Clans may have a bit of an advantage when it comes to skills for average troops, but the IS has a quality of scale that the Clans have never been able to match.
So what are the Clans going to do to keep up? Are they simply going to keep Clusters as they are (about 5 Trinaries) and they'll simply assign more than 1 Cluster to the attack, or will we perhaps see an increase in Cluster size to try to keep up with the IS forces, especially since most IS forces now have considerable conventional forces assigned to them?