Hi. I've done about 5 campaigns for A2, so what I have to say is only meant to help you, ok?
You need a bit more information from mission to mission and more connection between them.

You're jumping way over here to there without much information in the briefing, so I think more story telling is needed.
For example, Part 1, he is a pilot. Now in part 2 he is infantry. Why? You need to tell us why that is in the briefing.
Part 1, we make it to friendly camp. Then Part 2 starts but don't know story between the time at camp and now in this village with "gift from Nato". More connection with Nato involvement needed.

Part 2 to Part 3
Just starting Part 3 now.
Finished Part 2 but now I have to find Bastian. Who is Bastian? Why am I in this village having to escape?

I don't see the connection. So that is what I am trying to help with. Need more connection to make the story, if you're trying to make a story.

Otherwise, it's just a mission pack with missions (good missions btw!)

Hope this helps.....................

Here is the Campaign I am working on:
http://forums.bistudio.com/showthread.php?166344-SP-Campaign-L%C3%B3ngzh%C4%93ngh%C7%94d%C3%B2u-(Enter-the-Dragon)-by-Kommiekat&highlight=Enter+Dragon

My editing is not that great for A3 just yet, so I have not uploaded to STEAM, but I so have a story that is connection one event to the next................I hope you try them out and give me the same feed back as I have given you..........I just learning like others ;-}