I agree with the more stealth aspect, but when we accept, its more or less our choice how to deal with it.
We already agreed on not blwing up the building, because none of us wants this. We don't have to kill everyone. There are other distractions than blowing up buildings and massmurdering cops. And i'd rather go in there without anyone noticing. The real task is stealing, not killing. Though we all know, we can't always prevent it.
Yes, it is a challenge, but without it would be boring :-)
Edit: Since we get some money upfront, there is no harm in doing some research. Observe the building. Getting information on everyone who is allowed to enter, if anyone at all. Maybe Ares and KE are just hired as front door guards, who wouldn't even be allowed in there themselves. As soon as we are in there, it might be easy. After we get more information on whats going on, have collected backdoors and security codes, we could plan whats necessary to get in there. And if we then decide to not do it, because it might seem impossible, we could just sell the collected information to Gerrard. But quitting now without really knowing anything.... you are ruining your street cred ;-)
I would try it, even if its impossible, after all its just a game and i'd like to see how far we can get.