Change SkillBooks to 100%

Friendly (yet unsolicited) Maple nerd here~ o/

The reason this isn't a viable suggestion is based off a few major reasons:
1) Misunderstanding of the target audience of skill books
2) Economic principles that underpin the Maple economy
3) Neckson's game design

1. Misunderstanding of the target audience of skill books
If all that's stopping you from purchasing books is "the fear of failing" that means you're probably not at a stage of the game where you NEED the skill upgrade. It's like how a Lvl 80 player isn't going to start white scrolling to perfect his weapon. You only need MW20 and Genesis 30, when you NEED the upgrade to perhaps 1 hit something. At a point you're usually torn between "do I spend 100m+ to get a 2tma increase?" or "do I spend 100m+ to get a higher Genesis or MW, to get a WAY bigger increase". When the cost/benefit calculation points you to Genesis/MW, is when people usually buy the book. Don't ever feel peer pressured to buy it Only buy it if you NEED to 1 hit something, usually skeles as a bishop, or Petris as a AM.

2a. Economic principles that underpin the Maple economy
LETS ASSUME, we do change skill books to 100%, you're not wrong in saying that it might unlock a new group of people that you can sell books to. It definitely will unlock a player-base that hasn't reached the stage I mentioned above, to become potential skill book buyers. HOWEVER, just how many new potential buyers are we getting? At most, let's say its a 25% increase (which I'd say is a vast over-estimation). Genesis 30 is a 50% pass rate.

IF PREVIOUSLY, there were 100 people buying Gene 30. You'd probably sell 200 books, just because of the low pass rate. (Hypothetical numbers)
WITH CHANGES, there will be 125 people buying Gene 30. You would only sell 125 books.

As you can see, the nett sales of books would be way less eventually. As demand gets quenched faster. How about for a 70% pass rate like MW20?

IF PREVIOUSLY, there were 100 people buying MW20. You'd sell around 140-150 books.
WITH CHANGES, there will be 125 people buying MW20. You'd would only sell 125 books.

Of course, these numbers are purely hypothetical, so don't look too into them So if this suggestion was about unlocking more people and thus more sales, it wouldn't turn out as expected by the OP.

2b. Economic principles that underpin the Maple economy
What about from the buyer side? Surely it must make the books cheaper right? Well... What might happen is the market will correct itself for a short while. If the sellers knew that they can only sell 1 book to 1 person. Then you'd want to charge the highest amount possible. Probably the same as a 100% package right now, which is 2x the book cost.

However, this would probably be short lived, and due to the constant runs, there will be an oversurplus of books in stock. People will get desperate and as supply > demand, prices will rapidly fall. To the point where every skill book would be worthless.

3. Neckson's Game Design
Who cares if book prices are worthless right? Based on utilitarian thought, as long as the majority is happy (all the people that passed their 100% skill books) the minority (the runners) don't matter right?

Well... that's where Neckson's game design kicks in. Neckson designed the game so that late-game players that have attackers can (theoretically) earn money through bossing. Running bosses, then selling the drops (equips, pendant/helm, skill books). The other alternative is to sell leech as a mage (not sure if this was intended game design, but it became a thing). If you obliterate attacker's ability to make mesos, then mages will RISE TO POWER! Right? (Let's ignore the fact that this is unwanted from a balance stand point, as we don't want 2000 mages walking around)

Mages need customers too though :think: Leech buyers are usually attackers as it's slow to train one, and faster to buy leech as one. But if there's no end-game incentive to make an attacker, why even make an attacker? Mages will lose customers, inevitably leading to leech prices crashing as well.

With decreased meso turn over (via trades between players - aka purchasing skill books from attackers, buying leech from mages), the overall economy will probably suffer too.

Conclusion
Those would be a simple(ish) summary of why the suggest change wouldn't achieve the intended result. I hope you don't feel to discouraged though! Not all ideas work out, and I've definitely spewed our more unfeasible ideas than good ideas xD But it's that ONE good idea that matters

 

Oh sorry, you're talking about Mastery skill books right? xD