"upkeep" could be altered to "rent fee" or "gear maintenance" or something. Gear Maintenance would only need to be paid at start of every map.
Before a battle, you prep your gear and make sure everything works as it should. There is some cost related to this, smith needs a coin for the armor repair or fletcher need a coin to make more arrows... and so forth.
Actually the idea I had the moment the upkeep system was announced was to raise the level cap a bit and have a "wealth" skill. It's a skill without a governing attribute (like STR or AGI), which raises the worth of equipment you can wear. You get a basic equipment value which raises for every level a bit, but if you want to have more equipment, you have to spend points in that skill. So let's say on level 33 (the new soft level cap) without any skill point in that skill whatsoever you can run around with some cloth armour and a bastard sword, and that's it. But you will have amazing stats. On the other hand, if you spent 10 points in it, you can ride around on a plated charger with plate armour, but your stats will suck. Or you can spend like 5 points, have reasonable equipment and reasonable stats.
This system allows a much wider variety of builds, it allows weapons to finally be balanced properly by their value (which upkeep didn't allow, since it was not strict enough), you can keep your permanent equipment as long as you want, there is no RNG at the end of the round determining if you go broke or not, you don't have to downgrade equipment if you lost a few rounds in a row, clan members don't have better equip by default than random players who don't benefit from banner balance, you can't run around completely OP for a limited amount of time like you can with upkeep, owning a fief in strategus or trading a lot on the marketplace won't allow you to simply IGNORE the equipment restriction system any more, and utlimatively your equipment is not determined by the performance of the other people in your team. Only advantages, where ever you look. chadz said that my system would be "interesting" or something like that, but that they would probably stick with the upkeep system since it is what they implemented now and wouldn't want to create another system. If they only asked the community about the system change before starting to work upkeep and announcing it when it was already too late.