Ultimately it really depends on what you are comfortable with using. If you like using thermoplastics like worbla to make things then by all means share your process through pics or what have you with the community. The old saying that there is more than one way to skin a cat is very applicable to cosplay. Just when you think you e seen it all someone else comes up with a really new and cool way to do stuff. What you make is only limited by your imagination. A lot of people use a duct tap dummy or life cast to help them with their armor making. It give a reasonable-exact representation of your body and you can use cheap construction paper to make patterns and such.
As far as pepakura and being "too stupid". Pep work in and of itself is a very straight forward and easy process. Print everything, cut and score everything, test fit pieces and then glue everything up lining up the numbers as reference. I prefer using superglue for pep work because it sets fast and leaves no nasty residue all over like hot glue. Depending on the file size you might go through a lot. I recently went through 3 1/2 tubes for an ODST helmet. Pep work is mundane, boring and takes a long time but ultimately yields more detail with things like helmets IMO. You just have to take your time and be patient using the pep method. After its pepped you will need to harden it so that you can fix imperfections and make it last. Just have faith.
With foam I have not found a ton of "foam templates" that look like they work well. Over the past week I've tried several Pep files that have been "modified" for foam but ultimately it's just a pep file with the tabs deleted. I haven't liked the way any of them have turned out so I am doing a version of what you mentioned with Adobe Illustrator. I'm importing obj files into Illustrator from the pep files and tracing the front outlines. I take measurements in pepakura viewer and then add on things to the file to get it to look the way I want it to. I try it out with a piece of card stock or paper to see if it will work and if I like it I leave it. When I have some templates completely to my liking I will eventually post them in a thread when I get around to showing my ODST build I am in the process of. Biggest tip I can recommend is to be patient and don't be afraid of failure or wasting foam to try something out. I've always said I've never failed. I've always won or learned.
Foam is its own animal just like pepakura and if you use Illustrator to make your templates make sure you have a thorough grasp of techniques to use so you can plot out your templates to ensure the least amount of seams and cleanup work that you can. For example you can take something that is a box shape and make it out of 1 piece of foam instead of 5 if you sit and think about how everything will line up and by scoring and cutting the back side of the foam to bend it and make your edges.
As to foam and worbla keep in mind that the foam shrinks somewhat every time heat is applied to it and changes the dimensions and scale of it. It also can start to become brittle if overheated. I would hate for you to make a perfect part and then it is ruined by you having to heat the worbla over the foam under a heat gun constantly to push it around details and then your foam falls apart. Especially if you used hot glue to put it together. If it works great, but just food for thought. The worbla would make the outside rigid and yes a little more durable. If you seal the foam right (heat seal, then use modge podge/PVAu glue, plastidip or bulldog adhesion promoter) and paint you will find the foam is very durable. I prefer plastidip for detailed pieces to help retain the detail and adhesion promoter for everything else. A lot of people overlook the insides of the foam pieces. Make sure to seal the seams on the inside also. If something fails in foam armor it is usually where the seams are. I use contact cement for joining foam pieces because there's very seldom spill out and i don't have to worry about burning myself like using hot glue. Sweat will erode contact cement though over time so extra care has to be taken to seal it off so sweat won't get to it. Then again, sweat is very corrosive and can mess up almost anything.
If you haven't figured it out already I like to ramble. I've been away for a long time and apparently missed some changes that have happened to the 405th, but for now I'm back and I hope that in my ramblings something has helped. Looking forward to seeing what you come up with.
