So, a lot of what I do lately is to get a pulse of the community and see how they feel about certain aspects of pre-made adventures. After all, appealing to the majority is how money is made. I've seen a few lately on treasure, mostly because I was actively looking for them.
I haven't actually assigned any treasure yet, and what I currently have written has notes in red colored font about adding treasure rewards here. I know of the DMG parcel system, and the random loot system in the RC.
1) While I like the idea of parcels so you know exactly what you are giving out, this doesn't quite work in a pre made adventure due to not knowing where the party is as far as level, or where they may be within that level. For instance what if they already received 2 parcels of treasure, and the adventure gives them 10, now they have too much, or maybe in the course of the adventure they level, now I am giving out treasure from a lower level parcel.
2) Random might be better. I will be giving the DM what to give out, so they don't have to do as much work (after all pre-mades are all about not doing as much work). At the same time I can make sure I put magic items where I want to put them. Roll for random treasure for the rest of the hordes. I still have the same issue if they level, or if they start out already receiving treasure before they start. Also, random rolling has that nasty habit of making the players too powerful, or too weak.
3) Another is do what fits the adventure. If it makes sense for the bad guy to have a magic item, give them one. If no gold would be found in this situation, don't put any. This honestly doesn't fix any of the issues of the previous types, but it makes my design space that much easier. It will make things just a bit more difficult for the DM because they will have to make sure what I am giving out doesn't overpower his players.
4) Finally, I could always leave it up to the DM to determine what they want to do. After all they know what their players need and or want. I could just say Treasure: 0, 1, 2, 3,... parcels.
Looking over these options I'm thinking a bit of 3 and 4. Mostly because it seems that many DM's out there would like it so that treasure is defined by how much in parcels to give out, and let them determine what those parcels are. However, in order to keep a bit of the creative control, giving notes on what they should give out. Such as Treasure: 2 Parcels, One must be a magic item used by the [monster here], or perhaps random rolling treasure and then letting them pick an appropriate magic item. This collaborative effort of sorts between the designer and the DM seems to be the best way to go about it.
Honestly, in a way I'd think it would be better for parcels to be given in even more miniscule forms. Think small, medium and large. Four large parcels (the magic items), 4 medium (the current monetary parcel types), and 8 small. With each small parcel about 25% of a medium parcel. These are for when it makes sense for the creatures to have some treasure, but not a lot of it. Say, a Healing potion, a single gem, or a small stack of coins. Most likely I'm going to use the idea of small parcels in the adventures I create.
These small parcels can also create the idea of "optional treasure" where it's small enough that if they miss it, it won't hurt their wealth by level, if they collect all of them they are fine, and if they find a few extra it won't overpower them. The more I think about it and play with it, the more it makes sense to me.
If it comes out in the rules in the future, remember, you heard it here first.