From what I know, generally, a lot of the older DLCs are just either broken, tweaking, or nearly unusable, one of the ones I know for a fact is broken is the Oakville and SD40-S. The SD40-S has a broken horn, it's light are on in the editor, it's MU has the capability of a steam game on xbox, and it's interior is low poly. The Oakville route locomotives and cars are just uneditable, the route itself acts weird at night sometimes. The C40-8W refuses to work with anything that isn't the SPG coal cars unless you have a trailing unit that is compatible with every car or most of them, sometimes it'll work, sometimes it won't. There's a lot of other bugs and stuff with DLCs but I'm not gonna bore you with all of it. No offense but you guys should fix the current DLCs before bring another broken DLC into the game. Don't take this as an insult.
That's just the nature of software. But when your aim is to make money, you need to first find the money. You can't just halt production and fix every single existing bug, you'd end up going bankrupt.
With all the money they've made I think they can afford to fix a majority of the bugs that ca make certain things annoying, were been waiting for updates on Oakland for awhile now, we've been waiting for American things we want for awhile now, we've been told they would fix a lot of bugs, they told us the game would be multi-player, they've practically milked us into think that the game was improving, when the bug fixes never come, multi-player hasn't come, and the livery editor still has a lot of bugs they never fixed.