Pioneers doctrine would focus on the pioneer class of unit, offering a lot more variety for it.
0) veteran pioneers - armed with stg44s, but there are only two models, similar to coh1 pioneers in some ways. they get a free sprint and a wide variety of defensive emplacements and can trap buildings. they have increased armor and health comparable to a 4 man squad, but are vulnerable to explosions and snipers.
1) trap charges - unlike mines, these will be buried along a road and set off when a trigger node is activated which would use the soviet flare mine model, allowing for more devastating traps.
2) advanced preparations - allows pioneers to destroy terrain and leave chaotic spike traps in the mud, designed to trip up minesweepers. destroyed terrain will allow pioneers to apply a weak camouflage to themselves, lowering detection range 50%, only applies to pioneers. the purpose of destroying the terrain would be to cause a jam of enemy armor or infantry to more effectively use the trap charges. when used on already muddy terrain this would compound the movement penalties.
3) goliath bunker - a concrete bunker that controls goliaths. carbon copy of OKW goliath. if the doctrine is about traps, there's nowhere further to look than a goliath.
4) manpower repair - often when playing defensively, the opponent will use artillery at a faster rate than you can repair. similar to how conscripts can transfer men between squads, this ability will transfer a model to the building which cannot be destroyed by artillery, but it forces you to reinforce your squad as it loses a model or two depending on the size of the building. if the building is a bunker, the bunker being at full health will cause the model to attack from inside the bunker like it's a weapon crew.