Reading the forums as this being my first one this topic is one i had to come off the sidelines for. I also play a stone (ss)tanker. I agree that it is a challenge being a stone tank but i wouldnt change a thing heres why...I don't die.... I wouldnt give that up for nothing. Yea im slow, yea i look like a terd but with my build (ill get to that in a moment) gives me the option of playing two tanks Ill explain..
My build:
Stone armor
Stone skin (6 slotted maxed out)
earths embrace
Rooted (status protection)
Granit armor
Super Strength:
Jab (got to have somethng to hit while waiting on other toggles
Punch)
Taunt (for single target pulls hate to see it go in the new update)
Haymaker
Hand clap (just for fun rarely works on higher mobs but to see low level mobs go flying a hundred yards then get up stunned is pricelss

Knockout blow (slotted to the max some scrappers and blasters are in awe when i stand toe to toe with an arch villian and knock his ars up in the air for 400 plus in damage)
Rage (must have rooted and hasten to be effective)
Hurl (again another of those just for fun powers no real use fighting high level mobs)
waiting on my foot stomp.
Provoke (havent decided if im keeping after update)
Super Jump
Hasten (a must if you got granit)
Fitness/ stamina (a must for a stone tanker maxed out)
Imo you have two games here pre and post 32 for the stone tanker. pre 32 yes rely on rock armor and rooted post 32 drop rock armor pick up granit and with sprint slotted or ss the immobility of rooted is a non issue
Now when i want to solo or hit mobs fast with decent damage i dont go into granit form. I rely on stone skin however going against a mission boss or arc villian your in close quaters anyway so being immoble/slow is not an issue.
In a group i usually go exclusive granit armor with provoke i can take all that the mobs can give in the respec mission after my teammates dropped i was surronded by over a dozen freaks (including bosses) who couldnt move my health i was able to keep them at bay until my teammates got back from the hospital
So to sum up this rather looong post i think you deal with 2 different games and needs here before 32 immobility is a pain and somthing that has to be overcomed but your not having to take on the foes you do post 32 and its a non-issue then as your able to be mobile with ga and rooted.
24k lvl 40 tank champion
teck lvl 20 blaster champion
paragon panther lvl scrapper champion