Right now, primary stats are easy to cap (Might for melee dps, Agility for hunters, Vit for tanks, etc), while secondary stats are cap-able with a little work. With the introduction of the stat tomes, capping will become even easier, and an increase in level cap is likely to not make it harder (in fact, with gear stat inflation, it will likely become easier)
So, while adjusting caps and ratings conversions will help, what I think would be a great change is making tertiary stats (Will and Fate for physical classes, Might and Agility for tactical classes, and Might could also be tertiary for hunters) more helpful. Now, I am not suggesting on making it so that classes don't care about stat distribution (hunter would still want to cap Agility first and foremost, for example)
Two ideas (the first one being rather vague) for improving them:
-Give each class new passives to train (could be trained at odd levels that are not already covered by other passives) that would give conversions (2-for-1, 3-for-1, or the like) making tertiary stats into "mini"-primary/secondary stats. For example, a tanky class could get a passive that makes X Will be as effective for survival as 1 Vit. ("Your Will to survive and to defeat the darkness is strengthened" or some such). It could be ranked, such that X is largest at Rank 1 and shrinks as it ranks up, stopping before it really rivals primary survivability stats.
-Allow tertiary stats to boost caps on primary/secondary stats. In this, for physical classes, having a high Will could raise the cap for survivability stats (Vit, avoidance, mitigations) and a high Fate could raise the cap for dps stats (Might, Agility, Offense Rating, Crit, etc). For tactical classes, Might could be for survivability and Agility for dps/healing. For classes that mix it up, these cap raises could be added to trait-lines, so that, say, a Lead the Charge or Leader of Men Captain would be treated as a physical class (dps and tanking, repsectively), while a Hands of Healing Captain would be treated as tactical (healing, obviously).
So, while adjusting caps and ratings conversions will help, what I think would be a great change is making tertiary stats (Will and Fate for physical classes, Might and Agility for tactical classes, and Might could also be tertiary for hunters) more helpful. Now, I am not suggesting on making it so that classes don't care about stat distribution (hunter would still want to cap Agility first and foremost, for example)
Two ideas (the first one being rather vague) for improving them:
-Give each class new passives to train (could be trained at odd levels that are not already covered by other passives) that would give conversions (2-for-1, 3-for-1, or the like) making tertiary stats into "mini"-primary/secondary stats. For example, a tanky class could get a passive that makes X Will be as effective for survival as 1 Vit. ("Your Will to survive and to defeat the darkness is strengthened" or some such). It could be ranked, such that X is largest at Rank 1 and shrinks as it ranks up, stopping before it really rivals primary survivability stats.
-Allow tertiary stats to boost caps on primary/secondary stats. In this, for physical classes, having a high Will could raise the cap for survivability stats (Vit, avoidance, mitigations) and a high Fate could raise the cap for dps stats (Might, Agility, Offense Rating, Crit, etc). For tactical classes, Might could be for survivability and Agility for dps/healing. For classes that mix it up, these cap raises could be added to trait-lines, so that, say, a Lead the Charge or Leader of Men Captain would be treated as a physical class (dps and tanking, repsectively), while a Hands of Healing Captain would be treated as tactical (healing, obviously).