It seems one of the things ZOS is planning for patch 1.3.x to help address under-performing Stamina builds, in addition to the crafted set changes, is to raise the softcap for the Stamina resource slightly.
While this might seem like a nice quick fix on paper, in reality it accomplishes basically nothing to correct the situation. At best it might give you one extra block, bash, or roll dodge before you have to chug another potion, although not without consequences to other stats as I mention later.
While having more Stamina WILL be nice, since we have to "double dip" into our primary damage stat for ALL the defensive abilities (something magic users don't have to worry about at all), the REAL problem is the fact that all our class abilities (talking about specifically Nightblade here) that are CLEARLY melee-oriented, are scaled in terms of the damage they do off of how much Magic/Spell Power you have, NOT how much Stamina/Weapon Power you have!
For example take the Veiled Strike ability from the Shadow tree, our bread and butter "sneak up and stab it from stealth" melee rogue ability. It has a 5 meter range (as do both morphs), so no argument it is definitely a MELEE ability. The animation and sound effects are both obvious "stabby" melee effects as well.
It is a core ability of any Dual Wield or 2H melee build, to sneak up out of the shadows and surprise attack your enemy (one of the morphs is even called "Surprise Attack," the other "Concealed Weapon"). Yet the damage scales off of Magic/Spell Power NOT Stamina/Weapon Power as it should.
The same is true across the board. Assassin's Blade and morphs, as well as Teleport Strike and morphs, CLEARLY should scale off Stamina/Weapon Power as well, and yet they do not.
The problem here is that there are only so many stat points to shuffle around. Raising the soft cap on Stamina doesn't really make much difference, since to max your primary skill damage you still need to worry about capping Magic first, while having enough Health not to get 1-shot in trials.
What ends up happening, even after food buffs, is that the extra soft cap room on Stamina is basically wasted as there is no way to reach it without gimping your damage by lowering your Magic below the cap, or making yourself a glass dagger by gimping your Health.
The only REAL solution to the under-performing stamina builds is to re-evaluate which class abilities and morphs should scale off Stamina/Weapon Power and which off Magic/Spell Power.
Just the three Nightblade abilities listed here would make a huge difference if scaled off Stamina/Weapon Power.
Something else this could take into consideration is which weapon type you have equipped. If you have a stamina weapon equipped, have certain class abilities scale off Stamina/Weapon Power. If you have a staff equipped, have them scale off Magic/Spell Power.