The science victory is more about preventing other victories than gaining one. That's the nature of the beast, and I think that has its own unique gameplay style. You can't let some UN decisions slip through, massive wars will slow down your science, and if you ignore tourism, you'll get taken over via influence.
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Perhaps it's this. Scientifics are just defending, they need to keep a close eye on other civs to recognize threats, but then you don't really have your own unique weapons to counter those threats, and sorry but this isn't fun (this post exists to prove it). In vanilla you could bribe other AIs into fighting themselves, but now? You need massive (or very modern) armies to keep defended and you need some allied CSs to prevent hurting WC decisions (you need also some culture/tourism production to avoid being influenced, except that you really cannot, because if you do that then culture victory is at hand). So when you win a scientific victory is like: "I want to win this way no matter what", "I wan't to see how is it like once in a while" or "Damn, I cannot possibly finish off my last oponents in time, so I rather launch the rocket". That's why we say scientific victory isn't beloved here.
Also, non scientific civs have to keep an eye on other civs but on scientific ones. Scientific civs now are like the time endgame (what I dislike): if you cannot win before turn 440, then you'll lose to the scientific civ, but if you crumble that civ, you have 60 more turns to try. They aren't perceived as a threat, perhaps because they aren't much a threat, and get ignored or abused.
It's ok to not focus on anything until Middle-Ages or Renaissance (except for early warmongers). But then some civs start filling their museums and wonders, others start to pass some damaging WC ressolutions, and others start amassing and using huge conquering armies. What does the game offer for those pursuing a scientific victory? Not much. Trying to do everything (armies, cs and arts) while pushing for beaker production usually leaves this civ quite exposed. Also, if you want to research really fast, you have to stay very small, so you don't have much space for art pieces, nor terrain for deploying units, and most CS are too far away. What scientific civs really need is entertaining ways to slow down other civs, so they can launch the rocket.
While being technologically advanced has some advantages, you don't have anything
unique to do. It cannot hurt, gameplay wise, to let scientif civs have something else to threat other player's progress, so they have something to counter-attack, not only defend.
Their huggest weak point, that raising culture/tourism may make them lose the science path, could be addressed by making artifacts yield beakers along with culture. This increases artifacts demand, so it's making it a little more interesting for cultural civs too.
The other problem, not having something unique to do, can be addressed by this projects thing I proposed, or by any other already proposed thing that actually makes you do something.
or by 
) against the tourism leader. 
What do you think, Gazebo?
