Havnt got my PT up enough to get Blizz, but I was able to level fine on my Jugg using tank companions. Maybe a little slower then it could be, but its a lot more fun to use different companions once in a while. Heck Ill even respec depending on what companion I feel like using(which has a side benefit of also changing up my playstyle), but I play for fun/story and dont give a two hoots as to if I could have leveled a character a few hours earlier.
The only issue is keeping them all geared if you swap too often.
I love the character but in combat he annoys me by pulling himself towards mele DPS enemies rather then standing back and opening fire. Like Kalio Djannis for the IA the ranged tank companion is broken. Scadge is terrible too and gault is average so I use Torian,Mako and HK51
You can turn off companion abilities.