I think that these simple things would both be easy to put in game, and would be a huge improvement, for console at least. I'm probably not the first to suggest these.
1. Custom buff/debuff/dot tracker. Ez. When you slot a skill, turn tracker on or off.
This would not only help keep track of your own buffs, but make it easier to see if you hit the actual target you wanted.
Huge help for both pvp AND pve.
Along with this, maybe add a menu somewhere to track only buffs/debuffs you want tracked from others. I don't need to see a icon for rapids. Major courage, sure.
I would even settle for having your own in one line, and others above or below it in another.
Currently buff tracker is nearly useless.
2. Similar, but deserving of its own number in my list: Food/drink reminder. Idc if i have 1hr+ left. When it gets to 20 minutes, i do. At 5 to go it should turn red.
3. Penetration on character sheet.
'Nuff said.
4. When slotting cp for light and heavy attack damage, there should be a tooltip. Ez.
*5. Bonus, and doubtful I'll ever see it, is basically an in game 'build editor'. Basically the same thing that's on the uesp website, where you can see your stats with different sets, skills, etc.
ZOS you could even sell a 'theorycrafting station' in the crown store. C'mon.
Thanks for reading. I look forward to seeing these changes in future patch notes!