It's actually Jensaarai, unless the group/person you're referencing spells their name differently. Either way, a fan opinion does not make something fact. As it is applied in canon, Soresu has no outstanding shortcomings when used in a lightsaber combat situation. Quite the opposite, in fact. The reason they sent Obi-Wan after Grievous was because he was a master of Soresu, and that style was particularly well-suited for fending off Grievous' four-saber style, which utilized primarily power and ferocity (the same tenets of Djem So). Grievous defeated (and killed) dozens of other jedi in single combat throughout the clone wars, and Obi-Wan was the only one to ever even disarm him, much less defeat him. Even Mace Windu was outmatched and had to resort to the force instead of his saber skills (crushing Grievous' organ cage and giving him the iconic cough).

The point being: How was Obi-Wan even still alive if Soresu is an inferior style for lightsaber combat? Simply having superior skill clearly isn't the reason, since Mace Windu had just as much skill as Obi-Wan yet was unable to overcome Grievous in lightsaber combat. Even Anakin, who was more powerful and had as much training in Djem So as Obi-wan did in Soresu (Obi-Wan didn't start training in Soresu until after Qui-Gon died), couldn't break his defense, and paid for it with his limbs. 

Whatever source book you're drawing from isn't backed up by the evidence in the movies, whereas my source is primarily the movies.