Actually, they went to the 32lb hammer spring because they were selling pistols to the middle east military market who were using Egyptian ammo with incredibly hard primers.
Yes, the heavy hammer spring also slows down the slide travel which probably lengthens the life of the gun.
Most people follow Steven Camps advice and replace the hammer spring with a lighter 24 or 26 pound spring, then replace the recoil spring with a heavier 18.5 pound Wolff spring. That way you get the lighter trigger pull, along with the decreased slide velocity. It's the best of both worlds.
I find the Hi Power to be the best 9mm pistol on the planet. They're great guns in stock configuration, but they can be improved with time tested modifications.
And... you can do it yourself. If you watch the 40 minute video marked "Introducing The Browning Hi Power" in the link below, you can learn how to tear down a Hi Power into its component parts. It's pretty easy of you have proper tools.
http://www.celticarmory.com/media.html