How do you create your content approvals? By code or in the gui?

By GUI. The user get notifications that properties needs to be approved but it is all properties and we don't find somewhere to get at good overview.

That sounds a little strange. You shouldn't have to approve properties individually however I wonder whether the issue is that you have a page made up of multiple blocks and you need to approve each block separately? If so, there are a couple of approaches which may help. The first, and probably most comprehensive, would be to use projects. This allows you to make a number of changes across different content items then an approver can preview, approve and publish them all together which sounds like what you're trying to do.

Another approach would be to use inline blocks which would mean that inline block content would be stored on the page being reviewed and would be approved & published alongside the rest of the content. You'd still have your current issues with any shared blocks though and, additionally, it's arguably just as difficult to spot what's changed in an inline block as the version comparison tool will highlight that the content area has changed but won't highlight what the change is.

Agree, I'm not an editor so my knowloedge is not very good at this. But I guess you might get a notification on what is changed and then you review it and approves it.

I'll let the customer show me what he is experiencing.

Thanks!