I also finished the arc this weekend on a level 50 blaster with a so-so build (some premium IOs, some SOs, even a couple of DOs!). And it is pretty dang hard solo at that level. I died more than I am used to and got very close to dying a dozen more times. Part of that is dealing with Vahzilok -- their toxic vomit is hard to defend or resist, they can rez, and the explosions can catch you if you aren't constantly vigilant. Beyond that, it seemed that there were parts of the arc where there were more critters than usual for a 0/0 solo run -- the ones that come to mind are Cortex and his ambushes and some of the warehouse rooms. And as BlueThingy mentioned, the fires can get crazy. For me, it was trying to get a blinkie without dying. I made it, and then the ambush got me while the counter was going off. Luckily I had the [Return to Battle] temp power.
I had previously run this on my level 50+ namesake tank and it was difficult at points for him too.
I'm not advocating that it be watered down any more, but there should be flashing neon lights at the beginning that this is harder than usual and you might want to bring friends. Flashing neon is required because there is a lot of text to read and it has to stand out.