The UHV goals are a huge part of what makes the game so fun, and they're usually the only way to win - stability makes Domination or Conquest out of the question for most players, so wins by points or UVHs are the best options for winning. Still, some of the UHV goals will absolutely be over a casual player's head. Ta,e Byzantium, for instance - will a casual player know that the last goal pretty much requires them to kill Venice and Genoa? A casual player will probably get frustrated with just how badly stacked the deck is against the ERE - terrible stability, barbs, Arabs, Bulgarians, Italian attacks & the 4th crusade, early extra (Justinian's) plague, Seljuks, Mongols, Ottomans & slow research & production . . . all diverting precious resources from focusing on UHV goals.
However, even a casual player should know to expect some of these things to happen (assuming they have a basic knowledge of history which usually accompanies desire to play this game). The reference folder contains info on these events, but a casual player will probably not realise the folder even exists.
However, we can easily guide the casuals at RC stage the way RFC and SOI do - with a strong strategy wiki. At the beta stage, it's tough to do this, as a goal may change with each release, but at RC stage a thread could easily be made and managed to help out the stumped casual player. Post a loading screen hint or two about the strategy guide's site and some mentions in the civilopedia, and we'll make sure the casuals stand a chance.