My personal experience i had 2-3 points of luck from some items I obtained, and it did trigger pretty often. I was playing EA last night, and would say the luck chime would go off every 10-15 containers or so, which is a lot considering how many there are. Most of the time I think it was just gold though, I don't think it holds value over the other abilities but again, that's my personal opinion and I never tested it. Maybe the gold equates the value of pickpocketing?
My brother had bartering up to 5, so everything went to him to buy/ sell and after a few hours we had more money we knew what to do with.. 10k ish with the best gear we could find or buy within 4 hours or so
I was a thief, he was a persuasion bartering type. So if you have a larger party, having someone with luck isn't a bad idea, maybe to open the the big chests, not necessarily all the containers.
You said some people were skipping things to come back to them later and find "late game" items? That to me is a bit silly and I am not sure if that's worth it. For example you visit NPCs that sell books and gear a few levels later, they always have improvements in their gear to match your level and needs.. So you are never hungering for gear to progress. Plus you could do the same thing for pickpocketing. Since you can only do it once per NPC, you could wait til you are level 30 to pickpocket that guy in hopes of getting better gear, but when I pick someone, I browse, if they have some nice things, I take, if they have just a meh selection, i will revisit usually, if they are a frequent npc merchant anyway.
1. By playing the game and not skipping containers and content, I felt stronger than most encounters I faced, with a 2 man party, 2 levels behind, still slaughtered them. So skipping caches and remembering to come back and open them for hopes of an upgrade isn't worth it at all.
2. I don't think its much of an exploit. Sometimes we would reload before we opened a chest and the contents would be the same. Sometimes different. Not sure the rule behind it, but if you open a chest you've been "Saving up for" only to find level 2 gear because that trigger happens, it would be a bit disappointing.
Since I am going to have a 2 man party, I don't know if I would invest into it, I find sneaking, thievery to be my personal favorites and more useful to steal stuff before we kill magisters for example.. but then again its not perfect either. Sometimes I pickpocket and the inventory is empty, or lackluster. Or I pickpocket a key to just skip the encounter entirely and just unlock the door, but I still want to do the event for the experience, or not worry about getting caught stealing and reloading a save to avoid killing the whole town. Each of those abilities shine in the right moments, its just a matter of personal preference.
I am never lucky, and don't count on being lucky, so I steal, quietly