I tried out Pariah's on my magblade last weekend when running through Vet maelsrom. It seemed much more forgiving and went pretty smoothly compared to all-out DPS gear, and that's mostly just my lack of skill since I've only played magblade in a dozen dungeons over a couple months. Equip arcane pariah jewelry and two heavy pieces of armor. I added some CPs to light armor focus and play a Breton with a bunch of spell resistance, it was just enough to come close to completely maxing out all resistances when I reached 1/2 health without giving up light armor passives.

Heavy armor comes at the cost of a lot of sustain, a lot of damage and most of the time you don't die because of too much damage, you die because you run out of resources. If you're using abilities like refreshing path and sap essence/funnel health with siphoning strikes always up, you'll be able to sustain and heal yourself through anything even without a healer, then you have your shields.
I played heavy a long time ago, tried light and never went back. What you gain far outweighs what you give up.
Heavy armor is forgiving, if you don't know what you're doing and going to make a lot of mistakes like stated above for maelstrom arena. But as you get better, get familiar with mechanics, a lot of things can be avoided by simply getting out the way, blocking/dodging or 1 shield.
It's up to you.