Well... did you buy a pickup truck expecting a Mustang? Of course it's slow. Not too many people buy trucks for speed.
The Triton has its issues, definitely, but I love it. After replacing all the "common problem" parts (i.e. the cam phasers) these things seem to be pretty damn tough. If you want more power / speed, try upgrading your truck - new headers, cold air intake, new throttle body, throttle body spacer, new exhaust, and a custom tune AFTER all that is put on.
2005 F-150 Lariat [Current]
New plugs, coils, and AC compressor: 24 Oct 2013. I survived the 5.4L spark plug change and didn't break any!
Gibson stainless performance headers, Flowmaster 44 dual-out muffler: 10 Dec 2014