Per-character increased drop rates for first few kills of each pinnacle boss

What it is:
Give each character a limited pool of %more item drop bonus from each boss. With each kill it gets exhausted and it never gets replenished. It is not shared between bosses (depleting it for the Shaper does not deplete it for the Eater of Souls). This mechanic applies to all bosses which cost significant currency to attempt (e.g. Maven's Crucible), and not to any other bosses.

Motivation:
Taking on such a boss is risky because you are making a large investment. However, outside of SSF, there are players that will be able to take the boss at nearly no risk and usually very quickly, so they're converting the boss fragment into the loot drop table, so the market price very quickly approaches the expected value of the loot drop table, so a prudent player is usually better off selling the fragment - this mechanic aims to make it profitable to run the bosses yourself, and maybe try to push your secondary character who's weak against a certain boss to kill it; on SSF as well as trade, this mechanic would encourage variety of gameplay, but won't force it as long as the bonus is not too high.


Details:
- The bonus can be either a flat e.g. +50% more loot until it's exhausted, then becoming 0%, or it can gradually decrease with each kill. I like gradual decrease more because it matches how the most memorable and testing is the first kill, and then it gradually becomes routine.
- Alternatively the bonus can be account-wide, per-league (on Standard it resets once per year?).
- Obviously it makes sense to reduce overall drops from the boss so that the average across players is about the same. Alternatively don't do this, and let the economy sort itself out by lowering the prices of the drops.
- This suggestion also applies to PoE 2, with the same motivation.
- The loot bonus shouldn't scale multiplicatively with any loot bonuses from the boss, because that would force the players to try to wait to gear up and level up and then kill the hardest difficulty bosses from the start, instead of doing the content they're comfortable with. If a boss has a higher-difficulty version (like in PoE 2), then killing it could just exhaust the bonus more - you exhaust bonus equal to 1.5 lowest-difficulty boss kills, but you also get added value from the bonus equal to 1.5 lowest-difficulty boss kills. I don't think this is applicable to PoE 1 in its current version.
- Alternative idea: add some one-off rewards for the first kill or first few kills for bosses. PoE 2's passive skill awards are good and they achieve this, so maybe PoE 2 doesn't need this system.
- I don't know what to do with pinnacle boss fights that have an uber version - it makes sense to have it separately for both Maven and Uber Maven, those require separate fragments, but if we prefer to avoid having this bonus for too many bosses (which causes some problems), then it's better to only have it for the uber versions, because the regular ones can be defeated risk-free by many more players anyway. Maybe just have this for only all ubers, that's it.
- Concern: if the initial reward is too high compared to the risk, then the market price will be quite high, so the opposite problem might emerge - experienced players who actively trade would have to sell their boss fragments to get better returns than running them. Especially if the mechanic applies to 30 different things, then I can see how a lot of players will be doing their 1st and then 2nd of each, and it will raise its value by a lot compared to how much it would be worth for someone who's already done it a few times. This is undesirable for people who enjoy playing this content over and over.
- I recommend having it visible whether the bonus for a boss still active, the players will forget which bosses they've already killed.
- For the exact numbers, I'm thinking maybe 70% More drops for the first kill, then 40%, 30%, 20%, and again 20%, then no more; maybe nerf the overall loot numbers by 10% to avoid inflation. This is my thinking without doing math or serious thinking, or looking at data. (I'm expecting that the good parts of my post are taken and the bad are ignored or modified)
- This can also apply to blighted maps, enhanced breachstones, or whatever that is usually expensive even if it isn't a boss fight. (With the drawbacks I described previously).