• Allow you to remove every piece of followers base armor and weapons, so you can stop the hunting bow bug and the carry capacity bug. This also allows you to give them whatever you want them to wear/use, you can stop them using a bow if you want them to be melee for example.
  
• Have an option to remove the 'essential' status of npcs, I think most people can play the game knowing who is important and those who can't can keep the essential thing active. This stops things like unkillable legates after completing the civil war quest line. You could have a problem with dragon attacks though, maybe make the essential people only kill able by you.
  
• The ability to leave some followers at your house, kick the housecarl out of your house to make room for one follower.
  
• Increase in followers running speed, so they can keep up with you when you run, my followers are always lagging behind.
  
• Have an option with followers, so they pick up ingredients that you miss on your travels, also random loot with high value.
  
• Allowing followers to ride on horses, sitting behind you.
  
• A reusable 'whistle' power to call your horse, allowing people who don't fast travel (horses move to you when you fast travel) to call their horse. Possibly a power to scare your horse away as well, so they don't fight a dragon.
  
• A similar power to above that allows you to call a 'waiting' follower.
  
• Divorce, then remarrying.

I'd like to see less followers, but ones that you can control what abilities they use and when. They're so unpredictable and can make the game harder in parts when they attract unwanted attention or mindlessly trigger traps.

If they were to remove the essential flag on npcs, then I hope that they'd run for cover during dragon attacks and not try to fight them with their bare hands. I always hate when merchants are dead afterwards and during the fight, they don't try to get out of the way. Only guards, and the dragonborn, should be fighting them.

Pathfinding is the bigger issue with npcs lagging behind. If I'm traveling outdoors, I feel like I'm forced to stick to the roads so my follower doesn't get stuck, or take an alternate route, and end up getting attacked. Traveling with followers feels like babysitting, and that my character needs to hold their hand as to not get lost/separated.

Being able to "whistle" your horse would be a nice option, as they like to wander off, and many dungeons have you exit in a separate area, away from the dungeon entrance. I'm surprised that this option doesn't exist yet as many other games have such an option.

You could control what followers use if you had the ability to remove their base armor and weapons, it would also sort out the irritating bugs. That's the main thing for me to be honest, also point 2.