I think I have discovered the basis of how the amount of players works. The rebels get four activatins a round, and approximately 40 hitpoints (rounding each hero down to 10 hitpoints). This is why we have heroic and legendary. So my though is could the game be changed to include more than 5 players? Could we have, when playing with six players, rookiee - reduce your health by two. At the start of the round chose one player (for every player over 5) to gain the left behind token. A character with the left behind token may not activate this round and gains 1 block.

Or do you think that it is more likely that we will see more imperial units in each campaign?

That's an option, and it does have its merits. You would need to add a caveat to several missions though: For those missions where the Imp player needs to Wound all the Rebels to win, he still only needs to wound 4, rather than 5 or 6 of them.

In February this year we had a group of 5 or 6 players, in addition to myself (Imperial player). I just let one of them use an extra hero...Gaarkhan, I think? And then the last guy was happy just to operate the iPad Sound Board app that I had customized for use in our IA game. In addition to the blaster shots and lightsaber swish sounds, it had the Wilhelm scream (for the dying Stormtroopers), a monster snarl (for the Nexu), etc. And also some comical movie lines (..."I'm an idiot" from Tommy Boy, for example). This guy was having a blast, just watching us play and adding the sound effects at the appropriate times. It really was a group event, where everyone was fully involved. Now, I'm sure that not everyone would be content to run a Sound Board rather than a Hero, but this guy was.

To compensate for the extra Hero, I think I added an additional 2 Threat at the top of every round, or something like that. The main thing is that the game is exciting and everyone has fun...mission accomplished, in spades!

I want that sound board.

I like Shut Up and Sit Down's approach for the 6th player. The Empire becomes composed of Darth Darth and Darth Doff. They each get a few units and the imperial players alternate activations.

It also makes the imperial player not feel quite so bad when he's stomping the Rebel scum because he's stomping them with a buddy.

I want that sound board.

https://itunes.apple.com/us/app/soundslate/id368323490?mt=8

I did a whole 5 hero campaign with the following rules:

-2 health on heroes

Threat level increased by 1

Starting threat increased by threat level

Open groups increased by 1.

It worked quite well and felt very similar to my other 4p experiences.

I want that sound board.

https://itunes.apple.com/us/app/soundslate/id368323490?mt=8

Is it possible to handle this with an android phone?

"Look sir! Droids!"

I want that sound board.

https://itunes.apple.com/us/app/soundslate/id368323490?mt=8

Is it possible to handle this with an android phone?

I'm not sure, since I don't own any Android products. It may be that it's an iOS-only thing, because when I go to the developer's website I only see options for apple products. Sorry....