Stealth and AI: Agree but detection should be based on Perception (Wis) and movement on common sense (use cover or retreat/advance). The current system is yawn inducing, especially considering stealth is my favourite way to play pretty much any game.
The save system: Don't screw with my saves. Other games that did this gave me nightmares, especially with all the crashes. Also the battles here take so long that sometimes you have to stop playing in the middle due to rl issues. I have enough discipline to not savescum if this is how I have decided to play and it does not affect me how others play their game.
Eating food during fights: This is a typical video game thing but doesn't make sense for a 5e game. I would like to have a menu option to remove it but not to see it taken away entirely since some people like it.
Jump and sneak attack: I like your suggestion for this, however would rather have an actual disengage not attached to jump, we are not kangaroos.
As for spells and other things, I don't have much opinion other than this should be kept as close to 5e as possible.
Magic Missile will always hit unless the target uses the Shield spell (not in game yet.)
Warlocks only have 2 spell slots, however these can be recharged on short or long rests. Other spellcasters get their slots back on long rests
Light armour and some types of medium weigh less and do not give disadvantage on Stealth checks. Still reason enough for me to wear them.