Tomas, you are defending yourself rather well, but it is still not enough to convince.
cRPG is about making your own build, with the stuff you prefer the most. Your suggestion does indeed limit the OP choices, but it limits choices in general. There is little to no room for interesting hybrids or something like that. You can't be a 1hd cavalry/HA hybrid for example. Not an effective one, that is, which means something if you consider how little effective such a class would be nowadays.
I honour your attempt to remove the upkeep, you see the same problem like me. Apart from the basic intention to limit the equipment the whole upkeep and multiplier system was a game design catastrophe, and it was obivous as soon as the devs released it. But all those different issues need to be fixed as a whole, you can't fix upkeep or multiplier without the other.
I also think that your intention of fixing the internal balance of crossbows ir perfectly fine, but you make actually the same mistake like the devs with the upkeep system. As the initial means of limiting the choice (= offering a drawback = paying upkeep/paying with slots) due to the means making no difference between the choices (you always pay about the same amount or can evade it with only slightly worse armour/most crossbows cost the same amount of slots) doesn't work any more, you tweak the viability to limit the choices. Which is like implementing 1.000 weapons into your game, writing it on the box, but ingame there are only 5 viable choices. Which makes the game having 5 weapons, and being much less deep than what it seems to be.
The requirements for the limiting system are...
... actually limiting the OP choices without workaround over other aspects (e.g. less armour or trading on the market)
and
... linearly shifting efficiency and "price".