Funny thing is that Terry is quite good (IMO) in season 2 of 24. That's why I have to put some of the blame on the writing. It's got to be the most generic Felix appearance in the series.
I think it's more a case of the actor improving with age; around the time of TLD he gave some astonishingly bad performances in other films (Hawk the Slayer has to be seen to be believed!) yet he has carved out a fairly respectable career for himself in recent years on U.S television - you're right about his performance in 24 being pretty good, along with similar work in the likes of E.R.
He's brilliant in Lost, and I seem to remember him being quite good in Las Vegas too.