Lot of good stuff here. Some random thoughts:
Self coaching and going off of how you feel is a fun way to be a runner.
Following a pre-written training plan seems like a good way to get injured. Life gets in the way, and inevitably the smart thing is not going to be a template workout. That said, if you don't know much about running, or are inexperienced, a pre-written plan can be a good place to start.
Instead of having workout goal times, changing to fartlek style and running by time is a good way to stay within yourself and ends up working better in the long run.
My caveat to running by feel is that you can learn a lot about yourself by keeping a good running log. You can see what volume causes you to break down. You can see how doing workouts too frequently causes you to develop injuries or need a break. You can see you crushing workouts too hard ends up leading to injuries or burnout a week or 2 later. Or which type of workout leaves you hobbling for a few days. Then you can combine how you feel with some objective information.
Injured a lot and want to run by feel? Read Joe Henderson's Long Slow Distance.
A coach is useful to have as an objective observer. But I think it is more fun to make up my own training, so I would never have one.