I wouldn't use the word disappointing, those weren't disappointing as I kinda expected being problematic games but they are sad wastes of potential:
Inquisitor: Really fresh setting with awesome 2d art, ruined by awful gameplay, somebody took the concept of trash mobs and ran with it, when you aren't unveiling some creepy diabolical plot (the good parts of the game), you are eliminating endless trash mobs on a barely functional combat system, the game is almost unplayable. I gave up on the first time I had to withstand a "dungeon" that was more a gauntlet in tedium as if the developers were trying to see how much you could take before giving up.
Witcher 3 - Witcher 1 was trying to be a real RPG and had a eastern european atmosphere that was really interesting, Witcher 2 had entire different acts based on your choices with a really interesting narrative with choices everywhere, Witcher 3 was a really disappointing game. CDProjekt invested alot more on quantity over quality and the basic combat system is more simplistic than a game like Assassin Creed Origins, what is terrible, the loot is terrible, the character progression is terrible, the combat is terrible, the quests are repetitive asinine (follow the red cloud) popamole nonsense over and over, most of the content is terrible with copy pasted bandit encampments everywhere, there are more bandits than people on this game.
They failed into continuing Witcher 2 awesome narrative structure, the major choices of the game have consequences relegated to the end or near the end, many choices had really insignificant consequences. There are some moments where the game truly shine storywise with some well written really charismatic characters but those moments are islands on a sea of open world boredom, even some main quests feel like boredom being just a long string of cutscenes with questionable follow the questmarker "gameplay" that you would find on any MMO between the cutscenes.
Dragon Age 2: Dragon Age 1 was a controversial game here on the codex but it had its qualities and if Bioware had build upon them, we could had some nice RPGs from them, instead they gone on a path, dunno if it was incompetence as the most capable people with RPG background in Bioware left when EA bought them or it was EA cracking the whip, I dunno, but if there was still hope on Dragon Age 1, Dragon Age 2 ended any silly hopes I had on Bioware.
Everything that could go wrong, did, they tried pushing the game into a more action focus that failed miserably, the game is a mess of recycled content because of the short development cycle and the narrative is a prime example of what happen when the cretin idea that fantasy is just some excuse for "anything happens" is allowed to manifest without being contested. Even the art style is horrible, how a sequel can look worse than a previous game is a mystery I won't understand.