Are you still looking for feedback on this one? Ah well, you'll get it anyway and like it.
#1 Whatever you as a editor decide to provide me(the player) with. You know the mission better than anyone and the prefference should be yours and yours alone. The player will adjust however he can, depending on his own gamestyle when playing with what an editor provides. I personally, regardless of the friendlies on my side, when faced with leading a group large or small, take point and scout ahead to prepare my route before my men enter into an area that they are unable to maneuver in. The games AI calls for preassault planning and proper strategic approach. The more men I have under my command, the more lookouts and covering fire I have at my disposal. I almost never depend on the AI's ability to act and react on their own. When caught in urban warfare, I like to be accountable for myself only, unless the supposedly trained soliders can think and decide on their own. So to answer to the point? I will adjust to whatever you throw at me.
#2 Really depends on the funfactor. If there is plenty of ammo, plenty of cover, and the enemy is not approaching too heavy or too fast, I'll stick it out and welcome the challenge of staying alive. If the enemy is rediculously fast and heavy, ammo is scarce and cover is lite, I would flee as fast as I could. But then again, if the humvee had plenty of ammo, I would withdraw and engage as I withdrew, prolonging the battle as long as I could.
#3 I never expect a campaign to be replayable. why? because once the story is told, then there is no more surprise. The story is the purpose of the campaign, otherwise just make a slew of SP missions with differing background stories and objectives. The amount of missions should be enough to tell the story. If the story is pretty much told without any further twists, then it only prolongs the conclusion of the journey.
#4 I would download any sized campaign to try it once. If the first few missions are crap, I would probably stop playing and never download another from that editor. If it goes well, I would probably explore their future projects.
#5 I prefer short campaigns unless I can expect an immersive storyline. (but there are many who can not maintain a long interesting story line)
I feel that each mission within a campaign should be as enjoyable as the first and last. NO COMPROMISE. Be as different as you can be with each mission while maintaining a smooth story transition and paying close attention to details that will wow the player. Do not allow time frames to cause you compromise details. Because then you become just another editor. Music added just because you like it, is a recipe for failure and dislike by other players. The Music MUST prepare the mood, MUST compliment the gameplay, if it blares over the ambience, it destroys the players ability to absorb the missions mood and therefore only adds size to a missions download and nothing to its immersion. Sound is key to a successfully enjoyable mission. Sound forces the player to remember certain features of your mission without him/her trying to. It also brings the area to life if you add the correct subtle noises.
If the sound and music seem immersive from the start, I would download a 30 mission campaign with 700mb of addons as long as I was assured a rememberable experience.
Happy editing partner.