Without getting into much details.
How about buffing Shields in general(Battle spirit) and just an overall better scaling with health. Since you mostly have to run so much magicka recovery to sustain magsorc, lower the cost for some skills and increase the cost for using streak if casted again even more. This way you can for example use more dmg glyphs/mundus and perhaps sets if the shields are buffed and be able to put out the same dmg as all other classes does with procs/sets on a shield build.
Since everyone complains about streak, having shields buffed and increasing the cost of streak if casted again and maybe even increasing the duration to 6 seconds. This will make magsorc rely less on streaking and make it able to stand and fight with shields while only using streak when really needed and not spamming it.