He was actually traded to Portland with Steve Kerr for Steve Smith.
Portland's biggest FA signings to date are probably Rod Strickland, Kenny Anderson, Brian Grant, Andre Miller, and Wesley Matthews. All were average to good level starters but none of them were all star level players at the time. Portland has never had that level of free agent success but then relatively few active all stars ever actually go anywhere in FA.
Jim Jackson and Jamal Crawford were kind of a biggish deal I guess, until they weren't. Hibbert and Millsap both at least signed offer sheets.
Personally I think Portland's penchant for striking out on free agents is overstated. In the 90s we generally had some FA success due to the winning culture of the era and SPAM, but after that we struggled for awhile as overcoming the Jailblazers stigma was tough. I think now with a young playoff team led by a charismatic all star, the chances of getting another good level starter this summer are pretty high.