Reduce range so that mortarts can effectively counter fire on them, for the rest I think they perform fine.
That makes no sense. To give you some perspective, the German 8cm mortar had an effective range of 2400m. while the M116 howitzer around 8700m. Obviously the difference in game is not so big for balance reasons, but an infantry mortar able to counter mobile artillery makes no sense in either rl on in-game.
The pack howie also costs 380 manpower, 760 (!) for two of them. That is 120 more manpower than a Tiger for an already manpower-starved faction, again to put in perspective.
Double ISG is honestly only a problem against the brits, so I'd much rather see tweaks in their design over the nerf hammer for both it and the pack howie.