Expansion of Cross-Class skills

With the release of 2.1, many SMN are up in arms over the loss of thunder. I'm a fairly casual player, so I'm not so fussed about the damage but I was still disappointed to lose the extra variety the attack added. I'm aware of the addition of BLizzard II, but it made me think about the Cross-class system in general

As a system it feels pretty lacking and underwhelming. The available skills are quite limited in number and application. The "choice" we are given in reality doesn't feel like much of a choice because the available abilities are so limited.

I hope the devs will expand upon this system significantly as a way to add some small amount of flavor to our characters. I'm personally fine not having a skill tree or anything, but an expansion of this system would do a lot to give a feeling of customization.

I believe more skills can be made available without ruining class balance. Expanded cool-downs or increased usage cost; even decreased potency could give the flavor without ruining class balance. I hope the devs will consider implementing something like this in the future.