As much as it's entertaining that the loud minority in this thread think tanking is fine, I'd much rather they make tanking extremely faceroll so that there are actually tanks than to leave it the way it is where there are no tanks. If tanking were so fun and better than in other games, then why is there so few tanks? The answer: it's not. Or at least, not to the vast majority of people who play this game, which are indeed casual. I'm actually a former casual player myself and hardcore now, but even still, my guild which is doing Explosive Conflict right now can barely manage one, maybe two tanks at best. Our main tank is a tank alt and actually would rather DPS, but has to tank because there are none. The other tanks aren't on very much or are main spec DPS. Other than that, we have to get tanks from other guilds to tank for us because there are no tanks.
Bottom line, I don't care how rewarding tanking is in this game if there aren't even enough people who want to do it. I tanked a bit myself until I realized how bad everyone is. Every time a DPS would attack the wrong target it would make me rage and want to quit the group. Same with when a healer would ask for Guard, etc. Most people just don't know how to play and don't understand game mechanics. The game needs to be designed around that instead of ignoring it if it wants to survive any longer than it already will, which isn't that long judging by how many subs it's losing every quarter.
You got a mis-conception on why people don't tank. It's not because people feel that it's too hard but that it's not self gratifying on the basis that you don't see bigger numbers as you improve.
The standard for a good tank is one that is alive (and keeps others alive) at the end of a battle and that doesn't change from the beginning of the game to the end. DPS get self gratification by seeing bigger and bigger numbers so they feel that they are amazing and experience improvements as they play.
Your solution to the problem would simply remove what little motivation there is to play a tank. If you can't fail at tanking and there is no scale to show your success, why play to begin with? Someone else could do it just the same...
At least currently there is a clear distinction between those who know what they are doing vs those who don't. True self gratification is achieved by surviving what others can not do. That is why we tank!