Agree, it's simpler than English and some other languages, because there is some relatively consistent logic to it.

I still think the different between Ш and Щ is a bit muddy and hard to remember and occassionally I put и where there should be ы. But it doesn't feel complicated or impossible to master.

It is not always easy to guess which part of a word should be emphasized. But adding apostrophes to indicate would just complexity so I don't think that should be done.