I understand how CM worked, I used CM for years and I was part of the CM gang on BTT for years, it's quite the opposite, you are missing a thing here, and that is the variety of chips.
With CM for example if you were to mix 0.1 B you would get 0.64 + 0.032 + 0.004 but you could further split your chips into 3 x 0.032
or even split them again.
In your reserve idea, you have chips of the value:
0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5
that makes 0.9 of your reserves but if someone would want to go with the CM model he would deposit 0.4 BTC and want them split into 4 0.1 BTC chips, someone would deposit 0.5 and again would want 4 0.1 chips and two 0 0.05 chips.
With your liquidity, if you have 1.2 BTC and 0.7 stuck in 0.2 and 0.5 chips you would have no way of fulfilling an order of 9 0.1 chips, despite the order being lower than your reserve.
It's a matter of change, you need way more low-specific chips than the orders you're taking.
You're right, chipmixer has more variety in chips and more flexibility in splitting and combining chips, I think I'd have a hard time doing that.
In fact, my current test chips are 0.001,0.002,0.002,0.005,0.01,0.02,0.02,0.05,0.1,0.2,0.2,0.5, so it supports any amount of 0.001-0.009 directly, when the user deposits 0.4, the system will return the minimum number of chips in priority, that is, 0.2+0.2, when the user deposits 0.9, the system defaults to return the minimum number of chips, that is, 0.2+0.2, when When the user deposits 0.9, the system returns 0.2+0.2+0.5 by default, there is no way to split or merge according to the user's preference, splitting and merging is one of chipmixer's strengths, at present we can't do it, this is not as good as the chipmixer place!