I've been dealing with the issue of what the best method of collecting is for Imaginators, and I think I found it, at least for my situation. A little research has revealed that a figure of all but 2 battle classes will be available with wave 1 (the extra 2 being sentinel and bazooker, both of which available wave 2). This information means that by the time wave 2 is released you will have had an opportunity to try out all battle classes to decide which would fit best with each element. In terms of creating a character with crystals this is the best estimation you can have as to which class would fit which elements, as you can know with rough idea what the class attacks would be, but element attacks are a bit more difficult.
My conclusion is that you can try out classes with the figures then use this information to decide the best combo for your 1st creation crystals in each element, with relatively high success rate. If you are right and the 2 attacks go together then you can keep that crystal as the only one of that element, but if you're wrong you will now have tried out both the class attacks and the crystal specific element attacks and can now decide the better class for that element of crystal with your 2nd crystal.
By this strategy you will only needs between 10 and 20 crystals depending on your initial success rate, rather than the 100 people initially thought they might need to buy. Obviously you can't try out all element/class combos but you can create all the combos best for your own play style.
I don't know whether or not this long post will help any of you but I figured I could post my ideas so that you at least know that there are various options for how you go about buying them. There are those who will completely skip the feature and only use the crystal included in the starter pack, and those hardcore fans who will buy 100. But most will do neither and limit themselves to 10, so I'm saying there are options in between.
Feel free to use this post to share your buying plans for Imaginators, I'd certaibly be interested to hear.