For the future, OP, you can edit your posts to bypass the 1000 character limit. I know, it's counterintuitive and weird. Live and learn.

As for the topic in question, I also think cross class availability should be extended, especially considering some are things you NEED to cross-class(Hi, Provoke), or it would be very very unwise not to cross-class(Hey there Swiftcast). However, at the same time I think it might be messy because they never intended for that sort of thing, so you'd end up with skills like Blood for Blood and Raging Strikes on the same character. Remember in early PvP when Marauders used to do that? Man, that was rad. Probably not a good idea, but super rad.

Anyway. I think cross-classing and freedom of choice in character build in general should be redesigned from the ground up. In the current game you'd be silly to not play a job over a class in anything except PvP(And those are niche situations anyway, mostly those cuh-raaazy marauders) and generally speaking the only freedom in character choice is gear(Where there will always be BiS), 30 allocated stat points(Which, for most classes, stack 30 in their damage stat anyway), and five cross-skill slots, which every class has a definitive "Set" of, since generally speaking you get to pick... 5 out of around 10 tops, I believe, and some are just really bad(Why is skull sunder even cross-class?!). I feel like there should be more diversity among classes to help choose your playstyle- things that don't have incredibly obvious disadvantages compared to advantages, like 15 INT on an archer.

Though me personally, I think the best avenue for doing this would be to let individual class/job actions have different traits affecting them and let you choose between one of the traits. Like say, make the traits for Flash be Adds Blind/Costs TP instead of MP/Deals 50 potency damage to affected targets. Then get to choose only one with them, with them being reset with a Keeper's Hymn style item. Of course, I also think increased options for cross-class skills, preferably more choices, would also be a step in the right direction.