I'm pretty surprised to read this, I've used Rietveld (Gerrit is a fork from Rietveld) and it is entirely possible to review more than one commit at the time (with the option to review them as a unique patch or as individual steps)

But what I love is the option of squashing the commits (or perform any other operation), as the review is independent from the repo, meaning that I can push a clean commit instead of adding a lot of commit fixing issues, which gets a dirty commit tree.

That can be considered as "not showing the full code history", but I prefer to think about it as "only pushing to the repo code that sort of makes sense instead of lots of confusing ver small commits fixing typos"