Blizzard obviously want people to progress through Inferno and want people doing it cooperatively, not this whole "farm early Inferno over and over for higher ilvl gear on the auction house" wall that people are confronted with when they're introduced to Inferno.
The health on mobs still scales, just not their damage output. This is the way it should have been all along. When you add more people, your damage output increases, so the increased health makes sense, but increasing the damage was just dumb. Bring in 4 people to inferno act IV and your tanks can't stay up anymore because of the damage spikes. Collective survivability increases, but individual survivability stays the same no matter how many people you have. The only advantage is tactics. Mob damage
already inherently scales with mob health since the more health the mobs have, the more uptime the mobs have, and therefore the more damage they output. It's just consistent damage over a longer period of time, which is where the survivability challenge should have always came from. It was odd for Blizzard to make this mistake in the first place.
The inferno wall is entirely due to people not gearing correctly or using appropriate builds, which is partially Blizzard's fault for not including PvP in the original release. Obviously you need damage or tanking ability first depending on class, but a lot of people stop there. You need to add utility to your build and survivability to your gear. My demon hunter can clear an Azmodan quest chain inferno act 3 run in about 45 minutes right now and with the exception of an elite hulking phasebeast or soul lasher, he can survive a top damage hit or about 3 low damage hits from these mobs. You just need to have a good balance between vitality, +life %, armor, and resist all. (You'll note this is also what makes good PvP gear, since the damage from any given ability can be 100% ANY damage type.)
My DH has just over 60k base dps (this is without damage buffs - no sharpshooter or cull the weak), over 150k effective health (meaning between armor redux, resistance, and life, it would take over a 150k hit to one shot him), and just under 140 magic find. This is not including the survivability utility of my build, which is based around the Tactical Advantage passive. More survivability gives you a lot more uptime and keeps the mobs from healing which increases your effective dps as well as lowering repair costs considerably.
