You're right, never played ED, not sure why that matters here. the toolkit is the first and only online modding tool I've ever used, and it's hands down the worst modding experience I've ever had. It's sad, because there's so much potential in modding PC.
Like i said before, a good middleground would be a Viewer-tool. It's not the final uploads that are so annoying to wait for, it's the test iterations, so to speak.
But any offline tool surely won't happen, this isn't Unreal Engine or another generic engine, it's Frontier's In-House Render Engine.
They'd be careful to expose it again. Which might also be a reason it took so long for it to happen in the first place, the TMTK.
More servers, i second that.
I'd like to see more than 25 Slots as well. As much as i delete old item slots, i'm always at the limit.
I don't understand what the server does that I can't do at home. I get it if you're on a 4-core i3 or i5, 8-16GB RAM.. But I happen to have more. Way more. I'd like to have the choice at least. And a disclaimer "here you go, offline tool, but there's no support". Even that would be miles better than this waiting game.