I didn't really read everything posted here,but i really can't see what's the problem or what "extra-rules" are added.
I don't like people that claim an item just because they were the first ones that said "MINE" when it appeared and then never fight for it just so nobody else can have said item.So,maybe forcing people to RP and whatnot isn't nice,but keeping items just so other people can't have them despite having more skill and power than their current user isn't nice either.
An easy way to solve that problem is for people that claim canon items also accept challenges for them or if they don't want to fight,just give the weapon to someone that wants,since they are not using the item anyway.There are always exceptions to this,like if the owner is away for a short period of time or has a really good reason not to fight.
On the other hand,there are people that hoard items just for the sake of gaining more power,despite already having lots of other powerful jutsus/items.So maybe we can set a limit to how many stuff someone can claim at a time (including items/jutsus claimed by alts).
Also i can't see how "rules" can really affect your RP.Some rules are really good,otherwise we would have people with 7 natural elements,5 KGs,1 KT,countless of very powerful jutsus and a huge load of chakra. (well people like this already exist).Each char should have it's limits and weaknesses. Of course nobody forces no one to follow this rules (i have seen acads claiming KGs,KTs,etc. fighting in the zone and nobody started shouting at them or calling them names),but they shouldn't feel hated when other people that follow the rules don't want to RP with them.
I mean,i only joined SL for a year and i didn't find it that hard to respect some rules and use common-sense.Of course i am not perfect either,as i also have some things that wouldn't be possible in the Narutoverse,but i do try not to exaggerate my powers.
PS: While creating your own custom item sounds like a good idea,we will just have 10 [insert weapon name here] carried around by various people and all canon weapons will lose their uniqueness.Not to mention that people can and will use the powers of different canon swords and combine them into one OP sword.