HereForTheBeer: German paratroopers seem to be able to hold their own since they all carry some sort of automatic firearm.
On the offensive, infantry generally sucks. On the defense, they also suck. Or I'm using them wrong. ; ) One problem is that their range (ALT-R to see it) is really only the range against other troops and unarmored vehicles. You'll have one guy per squad with a ranged anti-tank weapon, and rest need to get to within about 1/3 the range to throw a satchel charge at a tank.
A couple, umm, tips, I suppose. Good chance you already know most of this:
Use Z-W to put them into a combat stance. This spreads them out a bit.
Enemy tanks tend to attack from max range so it doesn't help much having your troops in trenches since they won't be able to effectively fight back. About the only good it does is make them a little bit harder to kill, so it gives you more time to find the resources for a counter-attack. Oh, and it's a good defense against arty and other infantry.
If my troops get caught in the open against tanks, I charge the tanks instead of running away. They'll still die a horrible death, but at least they have a chance to disable the tracks - or maybe even destroy the tank - with satchel charges. Works a little better if you can have two or more squads attacking from different directions.
Assaulting a building or bunker is hit-or-miss. Try to use at least double the number of attackers versus defenders. ALT-right-click to charge into a building.
Troops in buildings are so-so. At least they'll heal. Tanks and arty will make quick work of them if they're hiding inside.
When defending, or even when paused during an in-progress attack, I use the D command a lot to set up an ambush. Seems to let you get off the first shot most times.
An important thing about troops: you can refill the ranks of a squad so long as at least one member survives. Move a supply truck nearby and press C. One full truck has enough supplies to restore a decimated squad to full strength. (note that this is also an easy way to get your field guns manned again).
Another important thing: Officers have binoculars, they make for so-so scouts. Their vision isn't quite as reliable as the sniper's but it's better than nothing - they have the same binocular range but they don't always see everything within that extended range. If you want to maneuver just the officer and not the entire squad, split the platoon into individual units using the C command. When he gets killed - and he will - use C again to re-form the squad and then get yourself a new officer by using the C command of a supply truck. Rinse, repeat, and you get an endless supply of binocular-equipped officers so long as at least one squad member (and one supply truck) survives.
And on binoculars: if a squad isn't moving then I often use the X command to extend the vision range, for early warning. Works best if you know from what direction you're going to be attacked (binocs narrows your view to something like a 30 or 60 degree arc, so you'll be more apt to get surprised from an off-axis attack). If the X isn't available, it means your officer died; use a truck to make a new one.