Obsolete don't reinstall. They appear to have gift bag stuff and then some.

Not really sure how I feel about it though... More sets == more possible fragmentation of complete sets.

I have 3/4 pieces of Dragon Toy artifact, 2/3 pieces of Belt of the Victor artifact, etc. If I were to mod anything in the original campaign, it would be to ensure that you get at least 1 large complete set/ assembled artifact in a playthrough.

In diablo 3 you will have the posibility of creating/buying the last piece of a set should you be in need (like you say 3/4, 2/3). I would love to see the same in KB. maybe the editor will help us.

Gift Bag appears as another campaign, so you have five in total: original one, gift bag, and three new ones including orcs. Gift bag is really only the original campaign plus items, so you can play it if you don't like new campaign for some reason.

No. The items featured in gift bag are in "Orcs on the march" campaign there's no gift bag campaign. There's orcs campaign, defender, champion and original AP. I don't know if the items are in defender of the crown or champion of the arena. As stated many times you'll need clean install of AP to install CW (i cant confirm this though because i installed AP and CW at the same time) but no there isnt any gift bag campaign.

But I had CW installed thanks to Stream "mistake" and checked it out thoroughly, so I stand by my comments. Note that I assume:
1. You had both KBAP and Gift Bag installed before updating to CW
2. that will work the same way after "new" release on Sept, 17th

In my case there are five campaigns. I had Gift Bag installed and is still works (and worked when CW was still unlocked, including old saves). More, the new campaigns from CW are still listed in the "downgraded" KBAP, and you can change to them, but only original one and Gift Bag work. The three new ones make the game crash (after selecting New Game), presumably because there are no resources.

The Steam did not clean install the KBAP! The date of install in Windows is the same as before. The settings are the same. The Gift Bag was installed before and remained installed. It only updated it (maybe 50% of files were changed and some added? They were changed back or deleted after "the fix").

Oh, and one thing. In KBCW every campaign has it's own color, and changes the buttons (New Game, Load Game, etc.) to that color. In my case the Gift Bag was purple. Not that any of it actually maters, because I don't believe anyone would install CW only to play Gift Bag or original campaign now, unless for sentiment ;)

Yes, but you don't need the gift bag anymore because its contents is already contained within orcs on the march. so it is obsolete now. And the other two scenarios don't have those artefacts. but I guess you can change that using the editor.

I dont know about the clean install thing that's just what the admins say here... anyways the point i made is that the gift bag campaign does not come with the CW and that the items are included in "orcs on the march" campaign (and possibly in def and champ).