The essence of the OP's proposal is Rozier and Crowder for a player of undetermined age and declining production, plus giving him $20 million/year for 5 years. IMO we can find a better use for our assets and cap space.
1989 born. What you mean?
He is still young
Are you going to say next Gianni's, Biyombo, Gasoline are all lying about their age
Even if Ibaka doesn't comeback what are we really losing? As much I like Crowder, Dozier these guys are bench/support players. Ibak a gives us a chance to beat the raptors and maybe take cav to 7