I think I posted a small list of the ones I've personally seen, on the other page.
Yup, took a gander
Anything from Bethesda fits with the "Tribunal" expansion that you mentioned (Dawnguard and Dragonborn being the best examples)
The Command and Conquer can be best fit with Gods And Kings for Civilization (though if I do recall, it's referred to as an expansion as opposed to DLC. It only contains one piece of DLC as it is a necessity in order for one of it's new 'missions' to be accessible [Spain DLC])
The DLC for that game though, does add new civilizations as well as scenarios which fall in line with new missions and units which the CnC expansion gave
The Secret Weapons pack adds "new weapons, vehicles, battles, factions, and a new gameplay mode". Most DLC packs that aren't the 99 cent variety fulfill these type of additions (I will note that they don't fulfill ALL the parameters ALL the time). Notable one being Killzone 2 map packs, GTA IV additions, Red Dead Redemption DLCs (individually, they fulfill an aspect, as a whole, they cover all of the additions)
I suppose, easiest way to put it is simply as I said earlier: Expansions are consolidated DLC
So technically, developers didn't shy away from expansions so much as they just broke them up into pieces allowing for earlier distribution one piece at a time. GOTY rolls out, and you've got the consolidated DLC (IE, Expansion pack) included with your original game (Not unlike when they sold expansions with the original game - Starcraft and Starcraft BW comes to mind)
So in conclusion, nothing changed other than how they distribute the content, and the pace of which it is distributed.
(I put this here in case you wanted to see how I look at things in different wording)Instead of looking at JUST one piece (or type) of DLC, look at ALL of the DLC for ONE particular game. What does all that content look like to you? To me, it looks like an expansion pack