Some people design some amazing ships. I typically don't. They look cool enough to me just because all ships look cool in GC2, but I'm not into the depth of design that some enjoy. I usually want to create slighly upgraded design #300 and get into production quickly. I upgrade my designs frequently, it seems.
It'd be nice if carrying over designs between games was optional, because I'd prefer that it not happen. It's exceptionally rare that I research the exact same tech sequence each game so it's exceptionally rare that I use a design from a previous game because it's exceptionally rare that it has the most optimal tech loadout for my current game. I end up deleting every custom design from the previous game as I play a game. I also tend to use different hulls and/or bling for warships between design bumps so I can tell the difference between them easier (rather than simply upgrading my existing design with newer components).
It would also be nice to have an option to not have stock designs ever show up. I never use them after week 8 or so (once I've researched the 1st drive upgrade and redesigned all core ships) and obsolete them as soon as they're available.