[Hitman]

So your left with SH4 or SH5 as a platform. (unless you don't mind "compatiblity modes" ) The former of which uses good ole, workable dat files, (as opposed to granny), has DDS texture compression, is a campaign writers wet dream ( I suppose SH5 is too, but its much harder to understand), and doesn't include a DRM.

Yes exactly. The biggest problem with SH5 is not just its flaws and bugs, but also that it requires a much higher programming level to be modded. It might be more open, but not for the average modder, only for the ones with a background in software development

1 - engine SH 5 is very good
2 - very hard made mod with SH 5. In SH 3 game was very good thinking and friendly for modding
3 - main weaks SH3 is (in my see) elderly engine and poor (in this time) grafics.
4 - SH 3 have many (now I have near 900-1000 ships and planes for SH 3) units what made for game. Like this have many land structures and objects made for SH 3. This very large database units can made excellent mods for game. In 2007 year I made my large mod "War Elite v.2.0" with use my data about germane submarine war WWII. And after it mod I can not made nothing more best, then "War Elite v.2.0" so I see game engine limited.
5 - SH 3 have limits in torpedo types in number torpedoes. It's problem can be cancel if rise number torpedoes types defore 1000 (for example). It can help made mods with more countryes (like it was in SH 4). Also SH 3 have limit on submarine types what can cancel if limite rise before 1000 types (for example)
6 - SH 5 have full submarines modelleing, but in my see it's was made before time, so it decision need more then power computers and most peoples in world can not buy sich power computers. In my see UBI need return in to modelling submarine like SH3/4.
7 - UBI need made AI subs what can dive and rise and launch torpedoes like it was in SH 1 (first game Silent hunter series).
8 - In my see UBI need return to graphic SH 3 game. My words base on base my mod "War Elite v.2.0". I see very large problem with weak video card during gaming in mod. It was so good modelling mod have many (few hundreds) various units (land, sea and air) and very large ships/planes routes. Good made mod need in more then hundreds various units for approachuing for reality. Every unit need video memory and every rout need no less then 1 unit and so need video memory.
9 - radio log (and possibility for modding) in SH 3 best then was made for SH4 and SH 5.
10 - UBI (if can made new germane sub sim) need made refueling (receive torpedoes) from submarines and ships in see before ending war patrol like it was in reality, but can not made in SH 3 total (engine limit).
11 - would be best, if UBI made detail patrol log with writing all facts during patrol.
12 - Mixies SH 3 and SH 5 not need, so SH3 have engine limit wat was use total in 2007 year in my mod "War Elite v.2.0". SH 5 not friendly for modding and I not see like can made mode like my "war Elite" in base SH 5 total...

-SH4 does already have instant resupply (Milk Cows) without having to reach a base and cock there.

-It also supports many more units,

- And there is a certain AI for torpedoes, as planes do actually drop them (Yes we have plane-dropped FIDOS in the german campaign late in the war!!)

There have been already some close attempts to add AI subs in SH4, IABL has managed one to dive and surface, and IIRC Privateer did too and showcased it with a Type XXIII. I bet that if many talented modders joined forces, some kind of satisfactory wolfpack action could be added to SH4