I am not sure wether we are talking about UP3 or DBW anymore
But, yes, DBW will be absolutely 100% geared towards offline play. There will be no considderation or compromise for any online functionality. In fact, if it is totally unplayable online, I wont loose 1 minute of sleep. This one is for offline players only. No discussion. Online players, and those "middle of the roaders", are welcome to use UP3 for their online gaming. Or any of the other gazillion packs that have been made especially for online gaming, and including the stock game, since it has ignored offline play for years now. No interference by any online player of any level will be tolerated with the DBW pack. Period.
All mods that are important for offline play, including some those Hades mentions above (if they are important to offline play) we will look towards making them available or asking the authors to help. Any mod geared towards online play is not even going to be considdered. This is going to be the first pack in history that is made exclusively for offline players, with no compromises. Noone has ever done this before, because online players have always climbed in and spoiled it.
Since the installation of UP3 is a requirement of this pack, anyone can at anytime switch to UP3 and play online. You can even mod UP3 to a large extent, and those things it has that make it not 100% suitable for offline players, are there for good reasons for the online crowd.
DBW is the opposite end of the coin. It is going to be for offline players only.
What is important to offline players: Maps, Missions, Campaigns, Objects, Nations, Markings, Mission Customization, QMB, AI behaviour, Cockpits, Eye candy, and all the planes you can eat. And, a stable standard core, that mission and campaignbuilders can use with confidence, knowing that nothing in this pack will ever be taken out, it will only be added to. So you can make a campaign now and say "requires DBW 1.0"
And two or three years from now, players of DBW 60.0, will still be able to play it.
How this kite will fly, we will see. Exactly how the structure will work, we will figure out as we go. What will be added and made to work or not int he future, the future will tell. All I know is, it is a first, it is exciting, and I have looked forward to this for 10 years.