I may be dis-remembering this, but it struck me at the time that we accumulated a lot of talent for Rick Aguilara under this same philosophy. Trade him for prospects once the season revealed its underbelly, and then sign him again in the winter. Rinse and repeat. If Kurt feels both the joy of playing for this team and the promise of its future, he will understand the motives behind a move and come right back at season's end.
You are "dis-remembering" a bit -- the first Aguilera trade brought back Frankie Rodriguez (oh how I wish we had gotten the "other" Francisco Rodriguez!
). He was once ranked #9 by BA, but that was as a low-A shortstop. His ranking had fallen as he switched to pitching and climbed the ladder, although he was still BA's #36 prospect before 1995 (although I think prospect rankings were much less accurate at the time). However, warning signs were there: he was pitching out of Boston's AAA bullpen for some reason, and his K rate had actually dropped in the AAA pen, and control issues were evident.
Plus, Aguilera returned to the Twins that offseason to be a starting pitcher. If he had stayed in his closer role, I suspect a return to the Twins may not have been his preferred destination.
And there was no rinse and repeat -- the second Aguilera trade brought back Lohse, but Aguilera did not return to the Twins (he retired after just one more season anyway).
Additionally, it's widely understood that it was easier to trade veterans for prospects in the mid-90s than today (veteran salaries were relatively cheaper, and there were no restrictions on draft or international bonuses). If Suzuki brings back a Sean Gilmartin type (to pull a name out of a hat), and is even slightly less likely to return... is it worth it? Especially if know you won't trust Pinto in the job in 2015 (or you may not trust him to break in young pitchers the rest of 2014, for that matter)?
Not saying I would do it, but it seems like the Twins would prefer extending him rather than trading him.