I think they could integrate him into the current Sheamus/Kozlov/Santino angle. Big Zeke could attack and put William Regal out of commission for no apparent reason. Then in the next Sheamus/Kozlov/Santino segment he could come out and destroy Kozlov, and Santino if he gets in the way. This would set up a confrontation between Big Zeke and Sheamus. He could say that he destroyed his former partner and mentor from ECW and accuse Sheamus of leaving ECW because he knew Big Zeke was the most dominant powerhouse and he could never match him. This would set up a mini feud between the two.
The only problem is it would probably put Sheamus over as the fan favorite. Not sure if Zeke could cut a promo to pull it of either. Anyway, it would make for some great entertainment though.