Hi Sylvie,
If it makes you feel any better, I'm on the fence about shop splitting, too.
Right now I have everything under one roof. I only have 60 items so it just doesn't make sense for me to split right now. I will have more expansion going on at some point in the future so more sections will be even more important then.
However...
I have been told by many people that I should do a split. One for my digital art stuff, one for the knitting and crochet and one for the animal stuff. (Among my top sellers is honey from my beehives.) This kind of split makes sense and it would mean likely each avenue would do better to be surrounded by their like items.
What keeps me from doing it are a few things...
One, time. Each shop would need its own setup, its own promotions, its own website, its own facebook page, its own emails, etc etc. Not to mention its own management (ie, log in to each individual account). I work a dayjob so I can't dedicate all the time needed to run multiple shops.
Each one also needs to have a DBA setup for each and every single one. Which wouldn't be a problem except some banks limit you on how many DBAs you can have. I need to check with my bank on what their limit is, I suspect it's only two which means more problems in me with my multiple shops.
Now the good thing about multiple DBAs, from what my CPA told me, tax-wise they can all go under the same blanket.
Bad news is if something happens with one shop (say, a lawsuit), it'll affect all of your other shops. So far as legal protection goes, each one should be it's own entity.
It's a pretty complicated situation and each scenario has its own pros and cons. So believe me when I say that I totally understand. XD