Tbh I think both those abilities are valuable enough to be slots in their own right.
The OKW Assault Package is different because there's not much of a performance boost over the stock upgrade path.
Flamers, however, are a major upgrade for Sappers.
It's already got smoke from the mortar. It was getting a bit smoke overkill.
Crew repair is much more important given the commander's tendency towards lots of <100 FU vehicles.
I think assault sections like IR.stg44,powerful but most time only one squad will upgrade,so it use one commander ability is waste,same as USF and UKF flamethrower upgrade,most time we traning engineer at the most two or three squads,and one of them will upgrade sweeper,so one weapon use one commander ability you don't think it waste?