Personally I prefer the current non-item healing abilities is restricted path, as other than the over proliferation of guard granting crafting bonuses and maybe making non-ability resurrection require a healing potion consumption, I like how the newer system makes classes more diverse in how they protect themselves or others.
Rogue defenses are based around stealth, movement, and preparation to represent that they are dexterious, cunning opponents that focus on preparation and misdirection. Lore wise their heal effects aren't true healing but representing their use of subterfuge to have avoided damage and/or fool enemies into attacking shadows.
Mages it makes sense that their defense should focus on prevention rather than after the fact healing and barriers still represent how their best able to protect others along with themselves. I'm not saying mages shouldn't have a support based specialization but rather that burst healing in combat, out side mastery abilities like ults/focus, isn't a thing mages should be able to do.
Warriors guard makes a world of sense, its proliferation on crafting doesn't so much but that is a different issue. You need to stop thinking of guard like armor but more akin to a representation of the fact that warriors are supposed to be masters of martial prowess, who through the years of their training know how to react in the heat of battle and thus prevent damage from ever happening, but at the same time there is only so much skill alone can do.