Most if not all of the actions done by Sinestro in this issue have been seen before by other lanterns. As many have stated before other lanterns have created rings before. The one people are forgetting is Mogo; whom was shelling out rings during the war of the green lanterns. Mogo is still a lantern albeit a rather large and powerful one.
As far as "saving the day with no effort" goes Sinestro simply created a better more complex construct. Sinestro's construct was designed to handle the situation in a very calculated and precise manor. This os more suited to how sinestro thinks. Hal is more of a "guns blazing" lantern, any of the GL corps would have handled the situation in a different way.
If you read the book you know Sinestro has a plan to stop his corps.
Finally as many have stated before in "Green Lantern Corps: Dark Side of Green" We meet a man who is part of the Guardians "corpse" division; which at one time was a team of 'lanterns' who did missions and went where it was too dark for the light. They function with black suits and use a different source of power than a ring. If this exists it shouldn't be that surprising that others might know about it.
From what i can tell Sinestro has displayed nothing surprising in this issue. All he had done is show his vast knowledge over the ring's capabilities. He did after all know about the yellow impurity as well and he was imprisoned in the power battery for a time; this coupled with his time as the Entity's host and leader of his own corps he has had plenty of time to discover the many secrets of the Guardians and the rings power.
(P.S.) Let us not forget he is wearing Hal's ring; which before belonging to Hal was owned by Abin Sur. The ring itself may be incredibly powerful.