I think you’ve hit the nail on the head – there are some workflows in other DAWs that might help you in your brainstorming process, but do those other DAWs fit your needs in other stages? Sounds like the answer is NO for you.
IMO, both Studio One and Reaper have some tools that I really love to use for this brainstorming/idea stage, but I’ll get to those in a minute.
Personally, when I’m using Cubase, I usually use the ancient tried and true approach of saving different versions to disk and reviewing the ideas later on, etc… For me, this approach has worked for decades with every DAW, so I’m used to it. It’s not efficient, it’s not great, but it’s what I do, and it works. I have a consistent file naming convention so I can find the files/ideas I want to review easily. Obviously, it’s not perfect, but I have no problem “externalizing” the havoc, it works well enough for me. If I’m working on one song or film cue, I might have dozens or occasionally even > 100 of idea files before I start narrowing down my ideas for the next stages. And Cubase has a good track import system in case I want to import one or more tracks from one of my idea files. Messy, yes, but it works.
Sometimes if I’m playing around with ideas on just one part of a composition (i.e. bass, vocals, lead, whatever), then I also duplicate tracks inside an idea project so I can compare and tweak and evolve that part as I work through ideas. I might create an additional 20+ tracks for one part, for example, group them in a folder “lead” for example, with only one track active at a time in the folder. I prefer that approach to track versions or lanes since I can see everything simultaneously AND I may change the patches or even plugins/chain as an idea evolves. However, it’s a resource-intensive process, sucking up the CPU and RAM since I’m duplicating and sometimes changing/adding plugins inside each iteration of an idea track… which can really get crazy sometimes, but it works for my creative flow, and then I’ll save that “version” (including the subversions of one instrument) to new files, and then keep on going… so I might have dozens of files with dozens of sub-ideas inside each one. It works for me. Eventually, I’ll comb through my ideas, and only import the ideas/tracks I want to develop further, thus freeing up resources again as I narrow down the focus of the composition. BUT ALL the old ideas are still saved with prior files… so I never lose them if I want to go back to hunt down a previous idea. It works for me. And again, we have good track import features in Cubase so it’s basically manageable.
Now as for other DAWs, I add their extra workflows to the above approach, and I’ll just give two examples that I often use in other DAWs… in this case, Studio One and Reaper. In each example below, the extra workflows that Studio One and Reaper have can drastically reduce the “external” chaos.
In Studio One, I LOVE the scratch pad feature. It fits right into my experimental process above, it adds a great tool to flesh out ideas. In fact, sometimes it can eliminate the need to save external versions, although I still do that out of habit. The scratch pad is extremely simple, and it does exactly what you think it will do… provide a separate space/timeline where you can work out your ideas without impacting your main timeline. And because the Studio One developers realized how helpful this could be, they added the most obvious thing you’d want with scratch pads, and that is scratch pad versions. So you can create as many scratch pad versions as you want, basically a great little repository of any and all of your ideas. Again, I love it. And BTW, if you experiment with the arranger features of Studio One in concert with scratch pads, you can have a lot of fun with ideas and keep them inside the same project space. Steinberg should add this feature to Cubase! EDIT: The only downside of this is that the scratch pad tracks mirror what the plugins are in the main timeline, so when I start exploring different plugin chains, for example, I still have to create extra tracks. It’s the only hangup of the scratch pad, which is otherwise fantastic.
And then there’s Reaper, which has the absolutely brilliant subprojects feature, which allows me to embed projects within projects within projects, indefinitely. I use subprojects primarily for sound design purposes these days, where they are indispensable to me. But they are also super helpful for brainstorming ideas too, especially once you really master how flexible subprojects can be, and it may change how you approach all projects TBH. It was a game changer when I discovered it. Basically, you can create a master/parent project that holds all your ideas and their variations and subvariations in one parent file. Each subproject can be sliced and rearranged and duplicated endlessly, letting you create basically infinite branches of ideas, all linked/embedded to the parent file. You’ll generate a LOT of files this way too, unfortunately, and it can also become messy, BUT at least you can contain ALL of the creative ideas in a massive hierarchy of parent/child projects. This embedded nature of projects within projects within projects is genius and lets you do some very creative exploration of ideas as non-destructively or destructively as you want. It’s not the same as Studio One scratchpads of course, it’s a different beast altogether. There are some things I would honestly prefer Studio One scratchpads for, but ultimately, Reaper subprojects are in theory even more powerful due to the infinite nesting you can do. It’s honestly one of the best features of Reaper. If I could tolerate Reaper for film scoring (I far prefer Cubase and Studio One for film work), then film scoring with Reaper subprojects would be the killer combo to manage massive film projects TBH. Sadly, Reaper lacks some features and workflows that I prefer inside Cubase and Studio One, so I tend to mainly use subprojects these days when working on sound design projects, where Reaper is especially useful and powerful.
Anyway, the best thing I can suggest with Cubase is to come up with your own workflow leveraging its strengths, and living with and accepting its shortcomings. I do find Cubase projects can get very messy with ideas, unfortunately, which is one of the reasons I use many different DAWs for different kinds of projects, but like you said, other DAWs don’t seem to meet your needs in other stages.
Good luck!