If Nicks runs the risk of being overshadowed by a 35 year old WR and TE, then why do we want him so badly? We obviously think he is better than our former 34 year old receiver.
Wayne was still beastly prior to getting hurt last year. Wayne and Luck have amazing chemistry. I fully believe that Hilton and Wayne will be the two go-to guys. Nicks will be a third option... depending on how much the Colts use their #1 TE over their #3 WR, he could be their fourth option.
Nicks probably wants the chance to prove he's one of the top WRs in the NFL and should eventually be paid like one. Can't really do that when you're the 3rd option on your team.