ABOUT ME: So returning BFG:A player and an ex-tabletop BFG player as well. That second part may be worth keeping in mind because I'm a 40k junky and much more interested in the 40K part of the game than in the RTT/RTS. To be honest, I tend to hate RTT/RTS games. So I might not be your target audience for the game. Also, many of setting's elements that appear to be annoying or confusing other players seem pretty clear to me. For instance, one player below complained of not understanding how troops were being replenished. I just assumed it'd be better at hive and penal worlds and moused over the interface numbers until I found troop replenishment. That kind of problem (and it is a problem) I cannot help you to find since I don't have it.

OVERALL: Enjoyed playing it and you guys have (dare I say) improved upon both the original campaign and also the tabletop BFG campaign rules. I think you've nicely blended the tactical fight layer with just enough grand strategy to give context to the meat of the game (the ship to ship battles).

-LOVE the little "timer" or campaign urgency mechanic in the lower right. So many strategy games make you feel like you're fighting with a script. You can do whatever you want and the enemy's actions only change when a scripted event occurs. This mechanic creates a bit more tension and a sense of urgency that stuff might just get worse if you don't hurry up and finish taking the sector.
-Love that as an Imperial player I have access to battlegroups from each of the Imperium's factions (under their own commanders no less) ... but see Suggestions below.
-Love that Spire's back.
-Like the UI. Only piece of information I couldn't find an answer to within the game when I looked for it and on that same screen was what battleplans do and how to get them. Also it looks 40k...without being unusable.
-Like the battleplan mechanic (once I figured it out). It adds a bit of the old data retrieval mission but without the tedium. Even gives you a reason to attack systems you cannot beat just to try and steal plans and run.
-The level of ship customization is just right for me for 40k. You go to war with the tools you have; not the ones you wish you did. The previous game's level of ship customization in which you could make every ship a finely honed scalpel designed to perform just one function felt wrong to me. There was no element to force me to adapt my tactics and learn. This fixes that nicely.
-The tech tree looks reasonable and each choice seems to add something without taking away from ship-driving on the battle maps.
-I like how the upgrade information is in tooltips on that screen. Thought that both simplified the UI design and helps me just focus on the part I'm reading. If I can't be bothered to spend a few minutes reading a five or ten lines of text I don't have any business playing a grand strategy campaign.
-The Capture Point mechanic I generally like for it's ability to bring interesting tactical elements to the combat game. A system defender can force the attacker to go for try for an elimination win by beginning the victory point race right away. I think that's a logical and interesting tactical choice. I don't mind chasing escorts around the map ... but I'm an old naval wargamer and I expect these things. YMMV. But there are problems with capture points...

-AI needs better understanding of the capture point mechanic and combat points values...specifically with respect to defense platforms. In the defense platform situation above, the defending AI always raced out to try and kill me...even though staying on its capture points was a better strategy. Sure, sometimes a well made AI should do silly things just because it's simulating a human (and in this case bloodthirsty Chaos worshiping humans) but a pair of light cruisers and attendant escorts charging away from perfectly good defensive position to attack a trio of full-up Imperial cruisers plus escorts EVERY TIME they are given the opportunity beggars belief. If the AI could be made to understand that its combat power advantage only exists within range of the Def. Plats. that would be a great step forward.
-Capture points seem … a little bland ... compared to the BFG:A1 missions. Sure, I was bad at some of those missions but they all made sense. Capture points are a bit abstract in comparison. And I guess some people don't enjoy chasing stealthed escorts around the map as much as I do either. I'm not sure about a good solution to this situation...see Suggestions below for a couple of tries. I know the devs are looking for an "extermination only" option for the campaign but that doesn't seem to solve the problem to me. Because then people will get bored blowing everything up.

-In the tabletop BFG campaign rules there were "Raids" (which deprived the enemy of the benefits of the system for one turn if the attacker won) and Battles (which transferred system control if the attacker won). The Raid/Battle decision determined which kind of scenario you played. Raids were Cruiser Clashes, Convoys, Raiders, Blockade Running, and one called "the Bait". Battles were larger affairs, including a 1 in six chance of an Exterminatus (which if the attacker won would destroy the planet). I wonder if you could use something like that. Say...Raid a system targeting a particular feature (like the shipyard) to deny the enemy its benefits for a number of turns...these Raids could use the current victory condition system (with capture points) or draw from the old BFG:A1 missions. A Battle would require an elimination victory and would be the equivalent of the old BFG Fleet Engagement scenario. Battles might be restricted to the "extermination" victory condition.
-Again from the tabletop game, there were "Sub-Plots" that each player could role before a mission...giving secondary victory objectives. You could keep the current victory conditions system and adapt some or all of the "sub-plots" from the tabletop to add variety to each engagement.
-I would pay for further campaigns developed as DLC and I definitely think that Adeptus Mechanicus and Space Marine campaigns would be good.