4d6 Drop Lowest is pretty good. it's random, you have the potential to get really good scores and really bad scores. Odds are that no one will be incredibly overpowered. As someone who likes to have flaws in their characters, this opens that up pretty well. However, I'm not a big fan of how it can lead to underwhelming or busted characters.
Points 0/27
Point Buy is the gold standard. It's super simple, raising a point above 8 cost one point except for 14 and 15 which cost 2. It will never be over powered or under powered. The problem is that you can never get higher than a 15 so nobody wants to take it. Most players would be happy to take 18 in a stat even if the rest of their stats are bad. Also, there's no random element. Because 4d6 Drop Lowest is better on average, if given the choice, players always choose 4d6 Drop Lowest if given the choice.
Here is how I would fix 4d6 drop lowest. I start by adding up the scores if the total is less than 70, I increase the lowest until the total is 70. If the total is greater than 80, I decrease the biggest stat until the total is less than 80. This does a few things that I really like. (I also redo everything if the result is impossible to roll) If you roll terribly, then you can get one really good stat. This is good for players that feel cursed by the dice gods. On the other hand, if you roll well, it balances you character nicely. Roll ridiculously well, and your guaranteed a bad stat, which I believe most characters should have. Most of the time, nothing will change. On average, this is still better than Point Buy, but less swingy than the standard 4d6 drop lowest. It is my attempt to enjoy the randomness of 4d6 Drop Lowest and the stability of Pointy Buy. I picked 70 and 80 by looking at the totals given by point Buy. There could be better high and low bounds.
Points 0/13
This is a work in progress and will probably be too complicated.