I'd love to see Sheamus booked against Undertaker at Wrestlemania. Provided that Taker is healthy enough to work his style of match and the two can gel decently in the ring, it wouldn't matter if Sheamus lost. Put on a match that excites the audience, they remember you for how good you looked and how exciting that moment was. I don't know if Orton's Wrestlemania match alone made him, but by the time those two were done with that program, Orton was made to look like a top tier heel.
I think it's a good payday for a guy in Sheamus' position. Brock doesn't need it. Cena could probably do a nice job with Taker, but I'd rather see what kind of rub that match could give to Sheamus, even if it were to be Taker's last.