As the other 2 have mentioned, Bus HL is a relatively easy course. We finished the 5 topics in the first year and now have the second year to just focus on our IA's, CUEGIS and Revision. It's a very doable and straightforward subject.
When it comes to history, I've never liked it, but it's up to you and what degree you want to pursue in uni. However, you have to consider the fact that if you choose to switch to Bus HL...you'd have to take it as an online course because that's what your school offers. This means that you would have to be more independent and put in the extra effort; but if what you want is to reduce your work load, I'd definitely recommend that you switch to Business HL. There's no weekly essays or anything like that; just purely understanding the concepts, key terms, theories and then applying them in case studies. There's of course more to bus HL than just case studies, but this is a very simplistic way to put it.
Hope this helped :)