I was under the impression that something along those lines was already implemented, but I paid close attention to the review button and concluded I can not see wether there are reviewing tasks due or not. Hence, I propose some kind of change of the button state.
I was under the impression that something along those lines was already implemented
No. What is implemented is this:
- If you have more than 1 k reputation: If there is an outstanding suggested edit to review, there is an orange square that takes you to the suggested-edits queue in the top bar. The number of reviewable edits is shown in the queue.
- If you have more than 2 k reputation: If there are three or more outstanding reviews, there the same orange square appears and takes you to the review overview. The number of reviews is shown in the queue. Both, the appearance of the square and the number within is not individualised to you and ignores reviews you already completed or skipped. Thus it is not reliable (see also here).
(The reputation levels are given for betas. It’s 2 k and 10 k on graduated sites.)
The latter was implemented in response to this feature request and was probably limited to higher-reputation users to avoid pushing lower-reputation users to review and instead let them explore the review system more slowly (see this answer), which is reasonable in my opinion.
I assume you are referring to the orange marker in the top bar. Unfortunately, it shows up whenever there are (at least three) items for review by anyone; it does not care whether you personally already had a look at some or all of them, or are otherwise ineligible to deal with them (e.g. if you raised a flag that caused a post to end up in a review queue). Developers cited efficiency reasons for this: It would consume too much time to check for the status of all review queues for each page view.