Possibly a mistake to read too much into this. The writers might just have wanted something light after the (neato but) dark "They keep killing..."
We like Gwen. She is everyman, the only human being in a group of the obnoxious (Owen) and the just plain alien (Jack). Eugene was also cheerfully human, and pleasantly nebbish in his fanboying of Torchwood and Gwen both.
Mr Pedia described this as being more of a traditional ghost story, instead of the horror that the series usually gives us. The thing about horror is that there is no fixing it. Suzie's report of her experience after death? Horror. "Something moving in the dark", and "nothing", and a desperate scramble to escape it. Eugene's experience was different, and his end a burst of light. His final attitude was optimistic.
Self-centered and somewhat jerkish behavior from Owen & Expository Jack throughout. Contrast this with Eugene's friend Gary, who kept repeating "I miss him". Even Eugene's dad manages to turn the experience into an opportunity for reconnection.
Overall message delivered a bit heavy-handedly, but Eugene's enthusiasm was infectious. Yes! Life goes by fast! Don't spend it waiting around for something that may never come. Enjoy what you have now. And his life did, ultimately, have meaning.
However, Torchwood is going to lose my viewing attention in favor of Heroes real soon. Okay, the BBC writers do better with dialog than the painfully earnest and on-the-nose Heroes writers do. But overall story arc wins. Also, vaguely pandering incoherent jokes like the stopwatch thing do not, in the end, endear the show to me.