Alliance rating should be a zero sum competition. It makes no sense for evey larger alliance to be rated 100. As a pax, if I like Star alliance more, it means I like Sky Team or One World less.
The description of what alliance rating is in the system and calculation (based on alliance age, number of members and amount of money contributed to alliance), seems fine. Except remove the components/caps that make ratings of all alliances converge to 100 (in the current formula).
Make the sum of all alliance ratings 100. If one alliance is up, another alliance is down. If a new alliance is formed, all the existing alliances are down. So the new allince rating will be a smaller number, probably between 10 and 20 (depending on number of alliances).
Currently, there is no gameplay benefit to being in alliance, only gameplay disadvantages. Starting with ~1% revenue fee. That could be 5% of airline profits, or it could be 100% of airline profits. Currently, it is money down the drain. Additionally, there are restrictions on players who alliances.
It was discussed in General Forum (but never followed up) that a game play benefit should be added to alliance membership. Adding the new alliance rating to CI would make the most sense.
So the final player CI would be sum of his own contribution (0 to 100) plus alliance rating contribution (generally 10 to 20)
Right now in MT7, there are 7 alliances with combined number of players of 117 (out of 650). It is still very early, about 3 RL days since alliances could be formed. The average alliance rating contribution would be 17%.
If there was some game play benefit (rather than only gameplay penalties) more players might participate in alliances, and there will be more alliances...