Thing is... I semi agree with your proposals.. and there isn't any way to reduce number of capital ships in a game.. putting them in Guard systems in okay IMO, but then again people just take a bribe ... so they can enter Guard system, then they re-do their repp.. so that isn't good way...
I don't know if that can be done but i would put lvl requirement for BBs to 90 (probably isn't possible due to vanilla FL and maximum level of 38) ... further more.. if you remove NB-S13 Jh.. people will just go to Frankfurt and then use S13 JH there and continue through Chugoku
About nerfing.. Yes.. I am pure fighter pilot and I fly couple bombers too, but I have to be objective here no matter how much i dislike Capitalship spamming and say that Battleships needs upgrade .. amour IMO and number of guns on ship... so they become usable in fleet battles.
It is unbelievable that 2 bombers can bring down one or two BBs at once... BBs should be strongholds and Fortresses in any battle .... On the other hand as much as repressive this sounds BBs should be flown ONLY by Official factions (I am talking about Battleships only) Why? Because every leader of official faction has experience in RP and they will know when and how to use BBs properly... and he/she can give keys of that BBs to member within the faction who have ability to fly it
Now as much as people whine and bash RM for doing Capship control in Rheinland i am thinking they are doing a good job (again I am talking again ONLY about RH BB, but also they should probably license couple independent players who are experience and known for goor RP and ability to fly BBs properly, however I disagree with limiting RH cruisers for use)
It is sad that all new players think that flying big ship makes them invincible and that is why we have so many independents flying around.. but then again in equally matched fight , capitals will loose every time when they enter battle against fighter/bomber squadron... (see that movie Keepers vs. all others in Delta.. like month ago) So basically for BCs and below there isn't solution that will result in decrease of numbers of capitals.. for BBs there is a hope but server rules have to be changed and that would require consensus within community..