Please continue to be condescending. Its great. You are the true forum warrior. You assume because my signature says healy sorc that I have never once respecced to damage? It probably never crossed your thick skull that I could say healy sorc because that's what I do when in rated warzones.
You are not asking for a madness mobility increase with these changes. Sure this would increase the lightning tree mobility, but it would also make them incredibly overpowered for PvE. Think about your only form of burst when playing the hybrid. The only decent burst in that spec is death field followed by a lightning barrage force lightning. If madness could cast force lightning in half the time that would essentially double the damage done by force lightning. That is not a mobility buff, that is a damage buff. As a min-maxed sorc you know that your force lightning does about 700 a tick on average without a crit. You should also know that a global cooldown is 1.5 seconds and can be reduced with alacrity. That is why nothing has a cast time of less than 1.5 seconds. What you are asking for is a spammable ability that hits for 2800 without crit that only takes one global cooldown to cast. How does this even remotely help your mobility? If you really play the hybrid you would know that force management is a non-issue in that spec, and that force lightning damage is front loaded, so half of it comes in the first second. If you are getting beat on and you think you half to cast a full force lightning, than your problem is not that you're a turret, its that you are playing this class wrong. Break off the force lightning. Nobody is forcing you to finish that channel.
In conclusion: You are asking for way too much with our class. The constant burst of lightning barrage would put sorcs in a place far too good. Your so called mobility buff would break them damage wise for PvP and PvE. If you would like it to take 1.5 seconds to cast half the normal damage you would be asking for a nerf, because any decent sorc knows it takes 1 second for that right now. Ask for a buff to our burst, or a slight damage increase... and a complete overhaul on lightning. That is what most sorcs want. Not to be broken, just to be viable.
P.S. It would help if you weren't so condescending in replying to the forums. Please do not assume things about players you have never played with or against. I spec damage quite frequently, and I use all the trees. I know what I am doing. I do not need to be told skills.