Lack of crew casualties =/= lack of loss.
Both ME2 & ME3 were rife with loss.
In ME2, you witnessed colonies wiped out by collectors, and saw the body piles and pods on the collector ship. You saw the results of the plague while recruiting Mordin, learned of Morinth's victims, saw the abuse on Prison Ship Purgatory & Pragia, saw Tali lose most of her team in 2 separate missions - shall I continue?
ME3 starts with heavy loss. Every moment throughout that entire game, millions are being harvested by the reapers. You see heavy losses in ground battles and ships explode. Walk around the Citadel, and you'll hear more stories of personal loss - there are even a couple of sidequests that have you delivering a loved one's last message, and you have some funerals to attend.
If players don't experience any of that as tragedy, it certainly isn't the writer's fault.
All the loss in Me2 and ME3 is only setting loss, its background loss. These losses only help create the glaring absence of loss for shepard. It is one of the reasons the dream sequences in ME3 feel "forced" for so many fans, Shepard is in this impermeable bubble the galaxy is falling apart but no one dies who he is close to except one terminally ill assassin who is doomed to die period and likely one Scientist who commits suicide. That is terrible writing.
There is no loss to Shepard's immediate circle of friends and co-works after the Me2 prologue with the exception of Thane and most likely mordrin solas. This means that when the galaxy is falling apart around Shepard, Shepard really doesn't experience the pain of losing people close to you. Jenkins' loss in ME1 was rather emotionally meaningless for the player because you get one dialogue scene with him before hand and then on the first mission at the very start he dies. There is zero chance to get emotionally invested with the character, this happens in Me2's prologue with the Normandy as well. At the very start poof the Normandy is gone and you lose twenty crew members of which only ONE was a crew member you could have a conversation with and he was the least sympatheticly presented character of the crew. It takes bioware to miraculously have his diary/journal survive the crash for Preston to be made sympathetic.
maybe there was some significance to Shepards death that caused him to be divinely touched and is able to magically protect his crew from the reapers cuz none of them die from the reapers after the ME2 prologue. Maybe that was the intent, if it was its poorly implemented, I don't know why the writing team went from writing a story that presented the costs of war on a PERSONAL level in ME1 but radically does a 180 so that the reapers and the reaper war can't seem to touch his crew.
"A single death is a tragedy and million deaths is a statistic." That is how loss is presented in the series and the creators realized this with the creation of the boy on earth, regardless of what the indoctrination crowd say, there is a direct quote in the art of mass effect p.16 "One child would be the face of the people of earth whom Shepard could not save." So it wasn't some convoluted hallucination, it was a child put there to create some type of emotional sense of loss. Which works up to a point but the dream sequences fail and a re vastly unpopular because there is no loss for Shepard's immediate social circle. No crew die, no squad mates dies except the one person you knew was going to die from a terminal illness and most likely one scientist who kills himself in an act of redemption. Both of which are NOT losses because of the war.
How does Shepard go through the war without losing a single friend to the war? The reapers can't inflict a single casualty to his crew or squad past the prologue of Me2. If they had had members die of your crew of your squad then the dream sequences would not feel forced, the drama of the losses during the war would resonate, the dialogue of soldiers lamenting and celebrating their fallen comrades would have tangible emotional connection. Hearing people talk about the loss of their homes, friends , families, the invasion of homeworlds would all have more impact because you the player would have suffered loss as well. But Shepard is such a god damn super dooper awesome trooper that this one person can go through the war and save every race, every crew member and every squadmate from the reapers.
i am not a child, I am not a teenager, I want mature adult stories that are not afraid to give me loss and tragedy. I can handle victory with a cost I don't need an "I win" button that gives me a cost free victory. I can handle losing a favourite companion, I can handle not being able to save everyone, to see the cost of victory as painful. If I had this then the bloody dream sequences would have made sense and not felt so bloody forced and ham handed. I want a mature title that is mature because it talks about things in a mature manner not just because it has T&A in it. Bioware can write like this they started the series like this and then they went to a Flash Gordon style serial where Shepard ALWAYS saves the day.
I pray to god that they create a cannon history for the reaper war where not every race survived, not every member of Shepard's team lived. I want there to be a sense of profound cost to the victory that has a personal sense of loss for player who played the original trilogy. The galaxy should feel like Europe circa 1919, devastated by war and the player should have a sense of loss to, to add personal emotional validity to the setting, because of the "I win" button most players don't have this sense of loss on a personal scale because the reapers didn't kill anyone on your team and there was no cost to victory because when things get sticky and difficult Shepard presses the "I win" button and its all solved with no cost. That's bad writing that's bad game design. This is not a Slam to the series or the developers this is constructive feed back, I want the series to mature and improve, I want it to evolve beyond the adolescent to the adult with regards to story telling.