In reference to your last 2 points, if a larger faction is unable to stockpile troops, then it would cost them a lot more to keep the out of the city (is that true?), if it is, then larger factions would have to regulate troop production in order to save them gold in order to buy equipment. With this being said it would make it very nice for the smaller factions who would not need so many troops to defend themselves or attack.
This takes away the advantage that bigger factions had within the amount of troops they can turn out rather than a small faction, making it more even.
Take 2 clans - Clan A (10 members) and Clan B (100 members)
Both have 1 Town and therefore 5k troops in it and then generate enough gold per day to support 1000 troops per player (after buying equipment).
So Clan A has 15,000 troops on 10 players and Clan B has 105,000 troops on 100 players whilst both clans have to mess about ensuring each individual player doesn't run out of gold.
Clearly Clan B already has an advantage here however If either clan wants to increase the troops they have further they have 4 choices
1) Generate more gold from trade - easier for Clan B since they have more members to make trade runs, protect S&D and raid.
2) Capture more fiefs for the garrison space - easier for Clan B since they have more troops to start with
3) Capture more fiefs to gain the trade tax - easier for Clan B since they have more troops to start with
4) Get better discounts on gear - easier for Clan B who can cap more fiefs but it could also be done via trade deals
Under your system as Clan B I would simply stomp Clan A. It would probably cost me 10k tickets since some of Clan A's members will be online at the right times to reinforce the Town, but it potentially satisfies all 4 of the above choices. I get more garrison capacity, more S&D, more tax and more PP to spend on gear discounts.
So what exactly is the benefit to Clan A here? Attacking Clan B is probably not practical as Clan B have more members to reinforce the fief in between attacks. Meanwhile Clan A has to keep more players inside or near their fief in case they get attacked so that's less traders as well. Its lose, lose!
At least now small clans are too much effort to kill for too little reward. Its also pretty easy for them to build up troops/gold and then whenever they go over 10k in their fiefs they can send the excess out for a battle or 2, safe in the knowledge that its unlikely they will be attacked back.
I agree its a bit boring now that most clans have built up so many troops they can't be touched, but there are better things to do about this. Incentives for using troops such as a time limit on strat and a proper scoreboard to decide the winner could work. Whilst reduced troop production rates based on renown, so that the more your clan fights the quicker you replace troops, might also have merit. Although i'm not 100% sure on that yet.