I know it's fun to play a game that has no limitations on anything, but upkeep was introduced due to mob rule honestly.
Most of the people begged for some way to get rid of the "all plate/all day on an armored horse" thing that was a constant. Before that, everyone dressed the same, there was no variety in the game at all. It's sad to say, but the min/maxers brought it on themselves, and it worked great for awhile.
A little time had gone by, and people started finding ways around the limitation, so a new way to bring some variety and common sense into the game was made. This was the loved/hated slots patch. Min/maxers screamed bloody murder, and some innocent hybrids got hurt as well, but it's still pretty playable. Pocket pikes are a thing of the past, archers can't carry a huge melee weapon and be effective archers, and Cavalry can't lance you, switch to sword, then lance you again.
It didn't address the issue with the upkeep workarounds, so we are back to "all plate/all day" though armored horses are lot less common. So I wouldn't be surprised if another upkeep increase is incoming in the future, since min/maxers are going to be min/maxers, and nobody likes them.
In my opinion, (not that it's worth a crap
) it extends the longevity of this game that there are limitations to what you can do. Slots makes people plan their load-out instead of the best of everything, and upkeep keeps endgame gear semi-rare (or at least, it's supposed to).