I couldn't find another thread committed to this topic, and I haven't been in this forum long. So if it does or has existed, please link accordingly.
This is not meant for a specific character build. But rather a list of guidelines / rules and limits for any character in general. Others have stated, including myself, that they set the diff high and gimp their character for a more challenging gameplay. I have thought about this and have concluded, from the post of others, that a very challenging aspect is to play the game set at normal and use your majors exclusively to level quickly and bring the enemies to a higher enemy to player ratio. I guess that's the way it was intended to start with. This may call for a custom class, as you will be potentially limited to MAJOR skills. This calls for no use of exploits.
This is a rough start to what will hopefully grow into a better and more challenging gaming experience.
You must eat and drink regularly / daily.
You can only eat meat, if you are next to a fire. ie...camp or fireplace.
You must drink twice a day, and when you eat.
You cannot pick up a weapon AND USE IT, if it is not one of your MAJOR skills.
You cannot fast travel. EVER
You cannot wear armor, if it is not a MAJOR skill.
Your HPs are limited. ( when and what amount? )
Maybe we should consider not using any MINOR skills at all? Aside from the obvious running and jumping. This is not carved in stone by any means. It is just a starting point for other ideas and comments. After 5 years, I'm sure that a lot of you have come up with a long and detailed list of this very nature.