So I really like the effort you've put into this post and as a hybrid sorc myself I do believe that we provide a TON of viability and will be highly represented in ranked warzones however I'm really surprised at this specific argument...
The problem here is that you take into account sorc bubble but act as if no other class has skills for the purpose of your numbers. Every other class has a defensive damage reduction ability... The Sorc bubble is a static fixed number of damage absorbed where as the warrior, merc, sniper shields have no limit to the amount of damage that they can prevent as they are % reductions not static numbers. Sorc's rely entirely on their ability to cc & kiting to keep themselves alive where a merc, marauder, jugg can simply pop their shield and in the case of warriors easily reduce 10k+dmg drastically increasing how long they can live. This also assumes there is no healer prolonging the fight(which makes dmg reduction more valuable the more someone is healed and the more dmg they are taking). This isn't a single player game and if you toss 4 people on a marauder to kill them they can easily last 2-4x as long as a sorc with 4 people on them.
I agree that 1v1 a hybrid sorc is extremely difficult to kill but a merc healer for example is IMPOSSIBLE to kill 1v1...
I just think it's way to early to come to any conclusions as we don't have true logs or 8v8 team organized competitive games. I think we will all be surprised by the team compositions that make their way to the top of rankings.