A Personal opinion.
In my opinion, the armory system is broken, but it can be fixed and be efficient.
Ok, we need an idea, I post my idea.
I think the problem is "we can equip too many skills".
We can decide to give a max number of points, let's say 250-300 at rank 50 (5-6point for rank).
Every skill has a cost, the cost is the level of the skill. For example Cure II costs 20 points.
If I want to equip Cure II and I'm a conjurer, I spend 20 points.
If I'm playing as.. a gladiator for example, I can still equip cure II, but it'll cost more, let's say 40 points.
Cure III will cost 48/250 points if I'm a conjurer, 96/250 for a gladiator.
Now I let maths and balance to others, but what does happen with this system?
250/50 =5 point for level so a gladiator can equip Cure II (and only that) when he is level 8.
Equip low level skill is still easy, but the highest skills will be expensive.
Of course SE has to balance skills and their level.
As I already written this is just a first draft. what do you think?