I like Oliver and Felicity as they are. Them in a relationship would be weird, especially when you know the romance is ultimately doomed since he's going to end up with Laurel.
Someone referenced Smallville and I think it would be exactly like the Lana plot after Lois was added; you know Clark is going to be with Lois sooner or later, so any time they try to do the Lana/Clark thing, it just feels like a waste of time.
Off topic: whose making the OT for season 2?
Well said Rei. Through the season I honestly saw zero chemistry between those two actors for anything more than a deep friendship. In fact, not to bring up Smallville yet again but it just reminds me of Chloe/Clark.