Got my S5 from the T-mo store last night, rooted it, and installed TWRP. I've tried changing the dpi using BuildProp Editor from the play store. The editor requested and was granted root. I changed the lcd_density value from 480 to 360 and saved the change. BuildProp Editor asked to restart, and I let it. On reboot, though, nothing changed. Do I need to change permissions on build.prop?
Have you tried using any of the Exposed Framework aps? I beleive there are some that allow you to mess with DPI - I have installed Exposed and am using a couple of the Exposed Framework aps like Gravity and Wannam Exposed to modify my status bar and a few other things - so it seems that Exposed plays nicely with the S5 ....Hope this helps...