Not only is he generally stronger than he was before, but he gained specific knowledge of some of Muur's best techniques the first time out, and what to expect.
....Such as? IIRC the attacks Muur was using to take Krayt were Maelstrom/Lightning/TK. Hell, even in sabers Muur was matching Vong! Krayt, if not outright beating him.
__________________ ”You presume limits to my power. There are none.”
They are angry because they have been forced to recognize that their hour has arrived; that the time has come to surrender power to Shimrra and the new order."
Other things- Last time Muur won when he absorbed Krayt's lightning, tossed it back, and Azlyn Rae's action preventing him from defending.
Now, we know Reborn Krayt can defend against lightning bare-handed (at least up to Wyyrlok's level), and considering last time, he's much less likely to toss out his own unless he has reason to believe that 'grabbing and tossing it back' won't be a problem.
With Krayt logically not using lightning offense as much (unless he is confident his expanded power is enough to simply overcome Muur's absorption- which I would not bet on), Muur will only be able to throw his own force power, which Krayt can likely defend against. Or in other words, this is more likely to be decided by sabers as Hett is unlikely to use moves he know can be used against him, and he'll have a good idea of what he can and can't block from Muur, having seen it before.
Once it's in melee, then Krayt has his saber skill and dark transfer in his corner.