All good feedback and we have a long list of changes to come, also sometime today (if all goes well) the entire site will have a big update! I look forward to the feedback on that :)
We use swap.hive because we are running second layer using hive engine, we are working on a way to simplify and even possibly allow users to buy art with any currency and have a swap service working in the background but we aren't quite there yet, we want to make sure the basic infrastructure and functionality is good first! thanks again for the feedback, noted ;)
It's human nature for most to only take into account the criticisms when getting feedback on a project, don't overlook the praise that went along with it. I do think you've done good work here and compare very well to big established site that have been at this for far longer.
I still don't understand the swaphive thing, and I doubt I would if you explained it a second time and even slower. Bottom line is you see the issue and you're working to make things simpler, and have a plan. I have no reason to doubt you :)