It's impossible to fix everything at once and it's impossible to please everyone. As a software engineer I'm also aware that just throwing more people at a project has diminishing returns and can even become counterproductive. I appreciate that ZOS at least appears to be trying to be more communicative with the Nightblade Updates post, But as far as what they are trying to prioritise goes I can only go on what patches have come out. It appears to me that bots seem to get priority over everything else. Sadly, I think this is a bit like the ever-waging war on drugs which just saps more and more resources while never achieving its aim.
I play a VR7 NB mostly pve with a bit of pvp and mostly solo as my main and a lvl 20 Sorc, strictly in phase with 2 other friends who do the same. I just find that the things I'd like them to prioritise don't really match with what I'd like to see. There's no real right or wrong here just personal preference. I would order things as follows.
1. Quest blockers
3. Fixing broken combat abilities (some hotfixes for NBs please)
4. Fix broken crafting - proper ingredients in VR. Enchanting levelling
5. Class balancing - let's not worry about nerfing anything other than clear exploits or making content any harder until things are working as stated.
6. environmental bugs - falling through the floor, getting stuck in walls etc.
7. extra content
8. bots and spam
I could make a bigger list, but I'll leave it at that. How would you prioritise?