If you want a TL:DR just skip to the Conclusion section.
Default Case percentages
Type | Chance
Lead | 80%
Iron | 15%
Bronze | 3%
Silver | 1.5%
Gold | 0.4%
Cobalt | 0.1%
When only considering the loadouts, and not the skins it translates into these Tier percentages;
Type | Chance
T3 | 80%
T2 | 15%
T1 | 5%
Buying a specific T1 loadouts costs 17500c. Cases cost 1000c.
Using 17.5 cases as the base, what would you expect?
Type | Total
T3 | 14
T2 | 2.625
T1 | 0.875
Trade-up costs are
T3->T2 3 + 500c
T2->T1 3+ 1000c
Trading into T1 only, you would get
14 / 3 = 4.667 + 2333.5c
(2.625 + 4.667) / 3 = 2.431 + 2431c
2.431 + 0.875 = 3.306 w 4764.5c
.: 3.306 T1 loadouts. 2.431 being a specific merc, and 0.875 being completely random. As well as costing 4764.5c extra for tradeups.
Translating 3.306T1 at the cost of 17500+4764.5 to get the cost down to 17500,
(17500+4764.5) / 3.306 = 6734.6
17500 / 6734.6 = 2.6
17500 / 2.6 = Random T1 loadout at 6730.8c
.: When looking at T1 loadouts and their costs the options are 17500 for a specific bronze loadout, or 17500 for 2.6 T1 for either completely randomized, or randomized loadout for a specific merc.
Taking these numbers and looking at the cost of Bronze Trade-In.
Trade In cost for a bronze is 3 Bronze + 1400c, to receive a random loadout for a specific merc.
With 9 loadouts per merc, and each merc having 1 great loadout, and maybe 2 more close loadouts.
(Assuming people either have a gun they prefer, or augment combination they prefer, 1-3 options supports this)
11% chance at best loadout.
22% chance at 2 close loadouts.
33% chance at either of the above.
33% chance to get a decent loadout, at the cost that is already greater than buying a specific loadout.
Conclusion:
Honestly, 3 bronze + 1400c for a 33% chance at a good loadout for a merc is too much when looking at a specific loadout costing 17500c, and that being the equivalent of 2.6 T1 loadouts through cases.
With only 33% chance of getting a good loadout for a specific merc, it should cost less than a specific loadout which is the equivalent of 2.6 T1 loadouts. So it should not cost 3. Argueably it could cost 2. But, I think the fair cost with a 33% chance is 1 bronze loadout + a slightly larger than 1400c cost, but not more than 3300c (Case equivalent of half of a T1 loadout).
With the cost for a specific loadout already set, getting a specific loadout through the combination of trade-ins, trade-ups, and cases should cost more due to possibility of getting high tier than bronze in the process. Argueably the amount could be 4 bronze depending on the value of the chance at higher tier, but I don’t feel 4 is within reason due very low chances at things above bronze. Therefore 3 bronze loadouts, as the current Trade-In has, is reasonable for getting a specific loadout from the trade-in. The credit cost should also stay within the 1k-3.3k range.