Prince Fielder's contract was a burden on the Tigers. It will be a burden on the Rangers. But the Rangers are in a much better position to deal with the $168 million than the Tigers, and quite frankly, they need Fielder more than Detroit did.
The situations faced by the Tigers and Rangers are quite different. While both teams are in large markets, their situations aren't equal. Texas has their core already locked up, while the Tigers really just have two members of their core locked up past 2015 – Justin Verlander and Anibal Sanchez. The Tigers still need to lock up 2013 AL Cy Young winner Max Scherzer, 2012 and 2013 AL MVP Miguel Cabrera, catcher Alex Avila, and starter Doug Fister. Swapping out Fielder's $24 million per year through 2019 for Kinsler's smaller salary of $11 to $17 million through 2017 gives them more flexibility.
Contrast that to the situation in Texas. 80% of their starting rotation, Yu Darvish, Derek Holland, Matt Harrison, and Martin Perez, are signed through 2017 (with the club holding an option on Holland for that season). Adrian Beltre is signed through 2015, with an option for 2016. Elvis Andrus is signed into the next decade. Even Alex Rios is under control through 2015 thanks to a club option. Assuming Jurickson Profar starts at second base this year, the only positions the Rangers need to take care of long-term are catcher (where Geovany Soto has just a one-year deal) and left field.
We can discuss whether or not a team would be better of with Kinsler or Fielder. This trade worked out well for both clubs, and with Fielder in the fold, the Rangers can finally stop crossing their fingers and toes that Mitch Moreland finally puts it all together. The 28-year old Moreland has a career .253/.318/.440 line in his 442 career games, and that's just not going to do it. Fielder is only a year and a half older, and his career-worst .279/.362/.457 smashes Moreland's career average.
The major sentiment among fans was that the Rangers had two options to deal with their holes on offense – trade Profar to fill the hole in the outfield, or spend a ton of money to fill in the gaps. They chose option three by going with the younger Profar at second, getting rid of the declining Kinsler, and upgrading at first base. They still have money to spend on an outfielder (or another bat) to fill in that gap, and they managed to get a little younger in the process.
Texas was going to have to make some sort of trade, and they made the one no one expected. While that alone doesn't make this trade a success for them, Kinsler was the best option for them to trade. If they would have gotten rid of him for prospects, that wouldn't have helped the team win in 2014 and 2015 – but trading him for a player like Fielder does. This trade keeps the Rangers competitive now and puts them in a better position in the future. What more can you really ask for in a trade like this?