When an edit to a question is pending, it's impossible (for users with sufficiently high reputation) to edit it without dealing with the pending edit. I'm not sure I like that behaviour in general, since it feels like I'm being forced to do something I might not want to do before I can do something I want to do, but I can see that it might help avoid edit conflicts. However, that's not true for edits to the tags and the text – it should be possible to edit the tags when an edit to the text is pending and vice versa. Currently the "edit tags" link doesn't even appear when an edit to the text is pending.
The problem with this is many-fold:
What if the new tags no longer fit the content after text edit ?
What if wrong tags give the wrong impression of which version of the problem is wanted to be solved ?
What happens if it looks like only a text edit is ongoing, but they then change or add tags ?
How can we easily ensure mutual exclusion, without adding to editing complexity ?
How to prevent multiple users coordinating to bump the post to the front page repeatedly or forever ?
How do we ensure the mods can rollback a post completely, while having said mutual exclusion ?
What should the time frame for each type of edit be ?
At least some of these need answering, before it's feasibility can even be considered ...