About Fire Blasters
Pros
Playing a Blaster was very new for me. In terms of range and AoE damage, they're similar to Defenders, but MUCH MORE POWERFUL. This is especially true of Fire who's secondary effect is extra damage. Played well, you will sail through a sea of orange damage numbers floating softly above the heads of your enemies as they run around the field screaming and on fire.
Blasters are not expected to Debuff, control, hold Aggro, heal, or support the team in any way other than blowing everything in sight to itty bitty molecules. It can be a relief to not have any expectations other than drawing too much aggro for the team to handle and trying not to die every other battle or so.
Theoretically, they've taken the inherent power, Defiance, which sucked rox before, and have turned it into something useful. Supposedly, you can now use your first three powers even when mezzed and you gain damage the longer you keep a combo going (something Blasters are very good at). If this is true, this could be a significant enhancement to the gameplay of Blasters.
Cons
Blasters spend a lot of time face down. I've seen it, and now I've experienced it. You will find yourself earning Debt Badges very early in the game compared to most and it's best to carry a bunch of Awakens with you at all times.
As you gain levels and experience playing your Blaster, you will spend less time dying, but because of your low hit points, you don't have much forgiveness for error. If you take on more than you expected, you're toast. A Controller will keep enemies locked down, a Tank can run through enemies or walls and not blink, Defenders use debuffs to keep things under control, but Blasters have few (if any) control powers and little defense. Therefore, they are generally the squishiest characters in the game.
In Summary
Where there aren't a lot of people to team with, I like to play Shazel and wipe enemies off the map. She's very good at soloing and I have turned up my difficulty to the medium setting with no problems (other than pausing to heal after some battles).
There are also certain concept characters that you must use a Blaster to create. For example, there are no Fire, Electricity, or Cold powersets for Defenders. If you want to run around with a wicked looking Assault Rifle or plant proximity bombs, a Blaster is your character.
Either way, be sure to spend some time on your story, look, and concept (as I always recommend) and you'll have plenty of fun.