I wonder why Bioware is so hesitant about this. This must be the one point of criticism about which pretty much everyone agrees. It's incomprehensible that we're stuck with what's clearly a testing outfit.
I agree and that says a lot to me. The BioWare fans can be fickle and are often at odds with one another, sometimes to extreme degrees. While I have heard a few defending the style of the outfit (I think the style is fine, other than too tight on the guys,) no one is defending the color beige. If the devs explained to folks that the dirt creeping up on the armor and clothes is an intended (if an utterly stupid) effect, gave us either color options or the option to wear our armor, I think players would be happy on that front. I think the largest amount of mods on nexus is the pajamas, and that's weird to me. I find it strange, because you'd figure that with all of the rest of the customization options, something as basic as this would have had more choices as well.
Also, I'm also with the OP. I spent a lot of time and effort in the game getting my armor together. Including color choices and overall style as well as stats. This also isn't cheap, and if they refuse to give us recolor options, then let us do that. Some of those armor sets look even better than what modders can offer with the clothes in some cases. Not knocking on the modders, far from it. They've done some amazing work, some of which I use. Sometimes though, I prefer the look of the in-game armor for characters like my rogue and my warrior.
I want the choice to wear that at Skyhold and toggle it off for moments like the romance conversations. I don't ask for toggles usually, because I know that most of the time it's easier said than done. This isn't one of those times, since I literally know it's as easy as flipping OFF to ON. I also wonder why it's so important to the design team that we are in stuck in that outfit no matter what. I've seen the screenshots of the armor at Skyhold. It looks like the armor itself was lit and shaded correctly for cutscenes, so no clue what the hold up is.
I don't get very cynical often about EA, or BioWare, or the game on the forums. Most of the time, I try to stick to the idea that life is too short for that. Plus, I think others in the BSN have the bitterness covered. 
However, I would be pretty damned annoyed if an option that should have been there from the start costs money. This should not require a pay DLC, due to the fact that almost everyone that I've talked to on the forums, on nexus and IRL hates the color of that outfit. I'm not trying to be demanding, but they should give us an armor toggle for Skyhold without charging for it.
My husband calls it the Skyhold Onesie. Or the Skyhold Footie PJs.