Well here is a concept for them...F2p gets 1 skill? because there is no incentive to craft f2p will choose a collection skill over a crafting skill. Providing incentive will make f2p want to craft thus the need to buy more skill slots or subscribe....CM purchases/subscriptions=money in their pockets!
While true, I disagree that your (or anyone's) new system would encourage F2P players to craft.
There are two flaws in your assessment:
#1 You are assuming that F2P players do not craft because the system is the way it is. The flaw in that assumption is that (as you point out), by default, a F2P character only has one crew skill slot. No amount of crafting system reform will
result in more F2P players wanting unlock crew skill slots to engage in crafting. You may think it will, but there is no guarantee it will
#2 You are assuming that F2P players are more dedicated to the game than they probably are. Working any sort of crafting system in an MMO takes some dedication. Given the fact that they are F2P and not subscribing, the exact opposite assumption is probably more accurate - that most F2P players are of the more casual variety and therefore probably would not want to dedicate time to crafting no matter how epically awesome the crafting system is/was. Basically even if BW opened up three crew skill slots to all F2P accounts tomorrow chances are that most of those accounts would have characters with three gathering/mission skills rather than one crafting and two others.