So, just a few ideas to change SWA to get longer campaigns and add balance to the whole.
I think it may be ridiculously easy.
Income
SWA kill teams earn too much credits. One could simply use the territory system of Necromunda (changing the names of the territories) with the maintenance table. This should mechanically punish large kill teams like orks and genestealer cults and give an edge to small teams like harlequins and grey knights. But it should balance itself out in a campaign since recruiting is so much costlier for the small teams anyway. Plus, small teams will have a hard time exploiting all their territories...
Experience
Using the Necromunda system, the only trick is figuring out what the starting experience for each team member should be.
In order for Necromunda gangs to be playable I guess new recruits should start at 20+1D6 like gangers, experienced fighters should start at 40+1D6, leaders and specialists at 60+1D6, and marines/superhumans should start at 100+1D6. Mere humans learn quickly or die in the process!
The advance system from SWA is pretty good, and the skills have been well designed imho. Simply replace "scavenger" in the guerilla table with the old "fixer" skill.
Scenarios
Use gang ratings. The gang with the lowest rating rolls the die on the scenario table and gets to choose who is the attacker.
Scrap the +4 bonus for orks and genestealer cults in some scenarios. +1 or +2 is way enough.
Serious injury
The SWA table is a bit simplistic, but the problem with the Necromunda table is that there are no bionics in SWA to deal with specific injuries, so I'm not sure how to deal with that. Perhaps introduce rare items to SWA...
The problem I see is that the rare items tables from Necromunda are very random.
A simpler way of getting rare items like bionics for kill teams should perhaps be considered... I'd suggest something as simple as a generic rare equipment list with costly items, only one of which can be bought after each game. A few rare items from Necromunda could also go on that list (like smoke bombs and screamers). No access to weapons and equipements from other kill teams.
Necromunda gangs would still get the old tables. Locals from the hive are much better at finding and trading stuff!
Agents/mercenaries
That's the really tricky part since some agents are obviously more powerful than others. Nasty ones like terminators or ogryns should cost a lot of credits. At least 50, if not more. But figuring out the point cost would require a lot of playtesting.
Alternatively, perhaps one could simply say that a kill team needs to sacrifice one of its territories to hire a special agent (perhaps even two for the most brutal ones). Of course, everyone would get rid of the shitty territories without a second thought but 1) it may prove a bad idea if you lose a territory to an opponent later in the campaign, and 2) it's a way to hurt teams that are too wealthy since they'll be more reluctant to sacrifice decent territories.
Maximum size of kill teams
I'd add +1 to the maximum for small kill teams (harlequins, grey knights and 'nids), +2 to "standard ones," and keep the Genestealer cult and orks where they are (orks are numerous enough as it is).
Necromunda gangs would have no upper limit: the reputation and glory earned by mere humans is enough to attract the inhabitants of the hive to fight with them for their homeworld against xenos and heretics!
I think it may be ridiculously easy.
Income
SWA kill teams earn too much credits. One could simply use the territory system of Necromunda (changing the names of the territories) with the maintenance table. This should mechanically punish large kill teams like orks and genestealer cults and give an edge to small teams like harlequins and grey knights. But it should balance itself out in a campaign since recruiting is so much costlier for the small teams anyway. Plus, small teams will have a hard time exploiting all their territories...
Experience
Using the Necromunda system, the only trick is figuring out what the starting experience for each team member should be.
In order for Necromunda gangs to be playable I guess new recruits should start at 20+1D6 like gangers, experienced fighters should start at 40+1D6, leaders and specialists at 60+1D6, and marines/superhumans should start at 100+1D6. Mere humans learn quickly or die in the process!
The advance system from SWA is pretty good, and the skills have been well designed imho. Simply replace "scavenger" in the guerilla table with the old "fixer" skill.
Scenarios
Use gang ratings. The gang with the lowest rating rolls the die on the scenario table and gets to choose who is the attacker.
Scrap the +4 bonus for orks and genestealer cults in some scenarios. +1 or +2 is way enough.
Serious injury
The SWA table is a bit simplistic, but the problem with the Necromunda table is that there are no bionics in SWA to deal with specific injuries, so I'm not sure how to deal with that. Perhaps introduce rare items to SWA...
The problem I see is that the rare items tables from Necromunda are very random.
A simpler way of getting rare items like bionics for kill teams should perhaps be considered... I'd suggest something as simple as a generic rare equipment list with costly items, only one of which can be bought after each game. A few rare items from Necromunda could also go on that list (like smoke bombs and screamers). No access to weapons and equipements from other kill teams.
Necromunda gangs would still get the old tables. Locals from the hive are much better at finding and trading stuff!
Agents/mercenaries
That's the really tricky part since some agents are obviously more powerful than others. Nasty ones like terminators or ogryns should cost a lot of credits. At least 50, if not more. But figuring out the point cost would require a lot of playtesting.
Alternatively, perhaps one could simply say that a kill team needs to sacrifice one of its territories to hire a special agent (perhaps even two for the most brutal ones). Of course, everyone would get rid of the shitty territories without a second thought but 1) it may prove a bad idea if you lose a territory to an opponent later in the campaign, and 2) it's a way to hurt teams that are too wealthy since they'll be more reluctant to sacrifice decent territories.
Maximum size of kill teams
I'd add +1 to the maximum for small kill teams (harlequins, grey knights and 'nids), +2 to "standard ones," and keep the Genestealer cult and orks where they are (orks are numerous enough as it is).
Necromunda gangs would have no upper limit: the reputation and glory earned by mere humans is enough to attract the inhabitants of the hive to fight with them for their homeworld against xenos and heretics!