Is there a reason to deny the transport actions in Wolf among the Sheep? Also shouldn't the raiders survival/destruction be worth VP, maybe 2 points to rebels if it falls, 2 to imps if it can escape?

In earlier versions I had the Raider being worth VP to both sides, but I found that it didn't work very well. I don't have notes on why exactly I made that decision, but I think it was because I thought it was either easier this way, or that giving the Imperials points for keeping the Raider alive made it too easy to just hit a few targets and jump out quickly. It's a judgement call on my part, but I did seriously consider scoring things in that way. Good question, though!

As for the transport being denied actions, that was for two reasons: simplicity (it is really just supposed to be a moving target), and to make balance easier. An actionless transport is much less likely to present the Rebel player with sneaky options and rules interactions I hadn't thought of.

At second thought it does seem superfluous to award VP since the rebels want to kill it anyway to end the scenario quickly to preserve the cargo and therefore their VP. It does seem to me that strategy wise, the imps should always go for the transport since without a reinforce or recover action it is worth 3 VP requiring the effort to kill (total damage dealt) as 2 VP worth of cargo containers (12 HP at 0 AG). I do see your dilemma as far as balance goes since the rebel already get a 40 squad point advantage. Pumping it to 70 with a fully operational GR-75, even if it cannot be upgraded might give the rebels too much of an edge.

The other thing is that the transport is such an obvious target that the Rebels may predict that you go for it first, and plan to have their reinforcements arrive in a position to bushwhack the Imperials as they finish off the transport.

Part of the metagame of this scenario is faking out your opponent about where you plan to have your forces arrive. Each side plans where their ships will arrive before they know where the enemy ships will be positioned. If the Imperial player isn't careful, they could walk right into a trap.