My level 41 hardcore blaster who survived numerous possible team wipes on Live would like to have a word with you.
Go blaster.
To add, I finally found a sentinel I like, Fire/ea, and yes, it can be more careless and it feels a bit like an AT for newbies or one for those who want to play more of a suicidal blaster style with less repercussions, but I would still take a blaster over it in the end. You can make a blaster safer due to smart play. You can't say the same for damage and a sentinel. I have yet to see a team go from point A to B faster than a heavy blaster team when it comes to PUGs.