I've seen a few crafting solutions tossed around in the past, but a lot of them seem quite complex, often involving minigames that are more suited to a game like Puzzle Pirates that focuses on puzzle elements. While puzzles are fine for some people (I for one like puzzles), it's a drastic genre shift that would be offputting to some players. I feel that crafting classes, like most other class types, should unlock new opportunities for you that aren't available normally. DoL classes grant a stealth ability that allows you to bypass monsters, DoW/DoM enable you to participate in battle content. Both of these are unique perks of levelling a class that you can't just simply by with gil or otherwise work around. I feel DoH should have things like this as well, but in allowing this we also need to make crafting accessible to everyone.
Which brings me to my solution to make crafting more engaging, less luck based, and yet stay accessible to everyone. This simple solution is to simply turn crafting into combat, essentially. Your progress is essentially the monster's HP. Your durability is essentially your HP. As you idle, it "auto-attacks", or in this case plays the standard crafting animation as progress goes up and durability goes down. Unless you're a fair bit above the level of the synthesis, your durability will hit 0 before your progress hits 100.
To fix this, you have a number of abilities on your action bar, a few of which are automatically set similarly to light shot and refill on archer. First off, you have rapid synthesis, which increases progress at the expense of durability (at the same ratio as your standard attack. It accomplishes the same thing basically as waiting a bit). The other ability is an important one: It restores durability at the cost of progress. Now, with this new system the existing abilities will need some changes, but it should be easy enough to make one into an ability to increase the rate progress goes up, another to reduce the rate durability goes down, another to boost the amount of durability restored when you repair, another to reduce progress cost for repair, and so forth.
In this system, craftmanship or mag. craftmanship (depending on synth) would determine progress calculations: How fast it raises, and how much it costs to repair. Control would affect durability calculations: How fast it drains, and how much is restored when you repair. These are both checked against the difficulty of the item to determine the final results, so just like how fighting an extremely tough monster can drain your HP faster than you can heal and not take much damage, an extremely tough synthesis is likely to drain your durability and raise progress slow enough that you lose more progress trying to keep your durability up than you gain over time... assuming you can even outcure the damage your durability is taking.
This also lends some support for group synthesis. With multiple crafters attempting to craft something, they each lend their craftmanship to the overall progress of the item. Each of them does have their own durability bar, which depletes depending on their control, which they can repair by taking from the group progress bar.
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With all that said, another change I'd like is one made to local leves. Make them time-based, and with a similar reward for completion that regional leves get, including possible time bonuses. It's a little frustrating how completing the leve only gives about as much xp as making one of the items in it. We can't even use guardian's favor for it as it is either.