No, it's only a fireball big enough to completely engulf Shepard and leave him lying in a pile of debris. That's much better.
It is, actually, since it's the difference between direct and indirect damage. People survive explosions and fireballs in the present day, without Lazarus' upgrades.
Easier to believe than seeing Shepard walk into a fireball. And survive a point black wave of space magic that should have shut down him "partly synthetic" bits
Not by much, considering the degree and trajectory of the debris' damage and Shepard's purely-organic nature at that point.
Yes she was wrong. It doesn't target Reapers. It targets "synthetic life". Of which Reapers happen to be. Of course, cyborgs are also potential synthetic life, but we won't get into that because Shepard is the only one at risk because 
Targeted =/= Eliminated. We have observable proof that the Crucible eliminates the Reapers (whom are complex hybrids of organics and synthetics) and those that "look" like Reapers. We also have proof that other forms of technology, other lives that rely on cybernetic processes, survived without a hitch.
Look sat the galaxy map. There is Reaper activity in systems without mass relays. The Normandy can even visit them. You gotta use fuel and travel to those worlds via FTL. But the Crucible managed to reach them too (at presumably FTL speeds as well) , because 
Because that's the way the technology of the Crucible works? Having a wide dispersal range off the relays doesn't immediately default it to magic.
And the only details given about the Crucible are 1) it uses a lot of energy and
therefore, it must be a weapon. What it does is never, ever addresed. TIM claims he can use it to control the Reapers, but never says how or how he even knows this.
"Wipe out the Reapers" is the very first thing communicated about the Crucible, which is consistently elaborated on (and, yes, feared in case there are drawbacks).
How long was Eva Core at the archives, and how long had TIM been researching Reaper tech?
Cybernetics in place where damage hurt brain. Relevant.
Not confused with synthetic life
in any form. Not targeted. Not relevant.