Problem here is, how do you maintain the same level of tension after 2 games? I see this complaint about all of the survival horror titles and really it's a mix of both players rose tinted memories and developers realising that they have to do something different or else they get the opposite complaints about not "evolving the gameplay". Seriously these games become less and less scary as you play through them until the only thing that does give you a scare is when there is loud music and a monster spawning from the wall, and if it goes down to relying on jump scares then the developers may as well stop making Dead Space games.
I really enjoyed Dead Space, and really liked Dead Space 2, but after playing for a few hours on both the horror faded away and the gameplay became that of any other action shooter where I started messing around with powers and trying new shots against necromorphs. Since the games have no system for say procedurally generating foes to keep you guessing if enemeis will spawn behind you or something the tension just fades away completely. Also if you play these games right you rarely need ammo, and health can be carried around in abundance.
Honestly I am not criticising your review here, but how many times can you have Isaac Clarke trapped on a derelict ship/space station before it starts nagging you? "Oh come on, how many times can necromorphs infest a giant ship?" or "Isaac got stuck on another city sized space station?". Also I think it's good to see EA developing the setting more with the Unitologists and their cultish actions being the main cause of the outbreaks in all three games. Eventually you are going to come face to face with the more militaristic side of this cult and I guess game 3 is as good as any really.
On the point of Isaac being more zen now, well think of him as Ellen Ripley in Aliens who goes from terrified Nostromo crew member to ass kicker in the space of 2 movies. Yeah she is scared of these creatures, but she has dealt with them enough now to be able to combat them effectively without breaking down into tears or going completely insane. Isaac is the same, especially after surviving 2 horrendous, nightmarish outbreaks.
Also the name Dead Space is more likely to be applied to the Physiological term, like Half life which wasn't referencing how Gordon freeman was 50 or something like that :) Just because it says Dead Space doesn't mean every game in the series must be set in space, hell the end chapters of the first game was on the planet the Ishimura was orbiting and that is where the outbreak started.