To explain the reasoning, everyone needs to be able to edit the wiki, not just us - not everyone knows that 1=fire and 4=light, etc. So we want to keep the monster/craft templates as simple as possible. That might not be important right now as we can create these templates from a script, but in future people may be administrating this wiki who don't have that knowledge.
Adding the DC sources is very useful, thanks! To keep it inline with the Monster cards it would make more sense to add it to the DC template as stage & source parameters (see Template:DC01). Then everything is in one place. If you need any help then let me know.