Operation Brevity: There is just no point in deploying any forward troops. Rather, you just consolidate around two-three defense points. Maybe add a few aux troops in the front so you can actually try to save these?
Battleaxe - this one is fun and almost ready. As in Brevity, it feels odd that you do really well with leaving the front objectives empty and let the British take them. Maybe add a few aux units here, e.g. Halfaya Pass? A winning strategy was also to block the road with mines. English troops never managed to fully remove them.
Dash to the wire - Tobruk is way too powerful and too aggressive. As far as I remember, they mostly waited to be relieved. I think if you put lots of heavy inf between the bunkers and AA behind them, this should work. Also, what happens when I actually manage to take it in the first mission? (Theoretically...)
Second offensive: I like this one, it is a tough back and forth. The extra units already deployed should be aux and have exp. After all, by now the Afrikakorps is a bunch of seasoned veterans.
Gazala Line: This is the mission I always had in mind when thinking how thrilling a Panzercorps port to OoB would be. Swinging around the south, aiming for their supply points, cutting off their front and winning against a bigger adversary - how awesome would that be? However, this mission needs some trigger and supply tweaking for this to work properly. I had the Panzercorps mission in the back of my head when deploying, but some things just dont work.
1. I punch through the southern minefields and kill the french garrison. Then I push along the road towards the airfield in the southeast. In Panzercorps, there is a message that a counterattack from the desert is coming. You need to add this message here, too. Otherwise, I get owned. That Italian bomber is useless. I get a Grant, but it is only aux, so I lose it afterwards.
2. There is no SAS attack. I camped those airfields for nothing. Odd. However, there are six (!!!) Spitfires coming from the desert swarming my airfields in the rear. This is a bit unfair.
3. I suggest you switch the objectives and triggers around to make this work. I took Tobruk, but had to cheat to finish this with a victory even though I consider my playthrough here a success. After taking the airfield and defeating the counterattack, I took the supply node on the road, punched through the weak bunker on the road and finally seized the (heavily defended) Tobruk. However, even when cutting off the British front's supply from the rear, north (Gruppe Hecker) and south, they never moved and had ample supply to hold out forever. I ran out of time to knock them out. I suggest you move all supply to Tobruk and the road along the coast and turn the objective into "seize Tobruk and 4 objectives" or make the front retreat automatically when Tobruk is taken. Otherwise, this mission will never work out fully.
Malta: I gave up after one turn. I flew a recon over the incoming British battle fleet and noped out. I think you dont need to scale up my forces because this would clutter the map too much. (Reminds of Crete back then...) Rather, scale back the British in terms of AA, aggressiveness, coastal batteries, naval assets and airforce. (So across the board) Right now, this is unwinnable.
. This feedback predates your recent changes, but you may find it useful anyway. I played on middle difficulty. I noticed that lot of the time I wasn't able to get the promised specialization point for a secondary objective. This occurred multiple times during this campaign.