http://media.moddb.com/images/groups/1/5/4477/Shaak_Ti_Even_Piell.jpg
I question whether or not that stuff is canon, but it does further establish that Shaak Ti is a extremely powerful Jedi master. this is further supported by Ti being established as follows.
"Shaak Ti is a master of the Makashi and Ataru forms in addition to her Legendary strength in the force. Known far as a cunning and serene Jedi, only the most skilled of the Order could stand against her!
-Star Wars: Adventures
Her martial prowess is further shown in her fight with an army of Magna-Guards. were she takes on them alone. not to mention she was able to break a Magna-Guards head with her knee during that fight and was proficient with a electro staff as well as Jar'Kai.
Even at her peak, Shaak Ti gave Starkiller hell and would have killed him were it not for this.
"On her last three words, she struck three blows that partially found their mark. The first burned a sizzling line down the apprentice's left shoulder. The second scored diagonally across his chest. The third would have skewered his right eye had he not held her back at the last minute with a desperate telekinetic block that stopped her lightsaber barely a millimeter from his skin. He could feel his eyelashes and eyebrows burning. The right side of his sight was entirely blue.
She gasped and staggered backward. Her lightsaber and her gaze dropped. A full half meter of red blade emerged from her stomach, then the rest came free with a hiss.
- The Force Unleashed
Her losses were all circumstantial, with Grevious she and the other jedi had been fighting the droids and were easily dispatched due to exhaustion. In her fight with grevious on corousant, exhaustion played a huge part as she and her fellow jedi spent the their time jumping from building and fighting magna-guards, not to mention she fought them alone and then pushed herself to her limit by using force speed to it highest degree, this, coupled with the fact that she fought against an army of magna-guards and even tanked hits from an electro staff, was obviously why Grevious was able to defeat her on Corousant.
Shaak Ti is extremely talented with the blade and her force powers are just as deadly. While Tiin is impressive, he doesn't have much in terms of actual feats, while Ti has both Hype, Accolades and Feats to support her as both a duelist an a force user. So this - in my opinion. is why Shaak Ti is on a higher level than both Drallig and Tiin. Though that is just my opinion.