Because of the subject of the thread and the universal laws of irony, this thread is fated to rise from the grave every so many years...
And, as we know from Bram Stoker, exposing it to daylight won't kill it...
As an aside, one of the things I found good about the short-lived "Moonlight" series is that the vampires could go about in daylight but they decayed faster, requiring more frequent feeding (blood) to halt and heal the decay.
As every supernatural thing they did entailed increased use of their resources (tired them made them decay) and therefore required more blood, it put an upper limit on what they could do between feeds (which they had to be careful about due to their version of the "Masquerade"). So doing something superhuman while being out in the sun might be possible - but undesireable under certain circumstances (like you don't know how long it will be before you can safely feed - which is probably most the time as "seeing the future" is not one of their powers).
I don't see why, in a game context, removing a vamp's vulnerability to sunlight requires the removal of an advantage or the imposition of another weakness to "balance" it - it's not like it's their only weakness and they're not meant to be easy to get rid of, anyway.
They managed to get by without exposing vampires to daylight in the original Dracula... which, iirc, mentioned wild dog rose also adversely affects vampires - something you don't often see mentioned in many modern books/movies (one of the Fright Night movies being the only thing I can think of - and apparently the character got the idea from reading Stoker's Dracula).
A former GM for one of our games would have given her soul for vampires that were immune to sunlight. Our standard response to being told the room was filled with pale, hungry-looking humanoids was: the fighter would yell "EYES!" whereupon my Drow and the other subterranean members of our party would shut and avert our eyes then the fighter would draw and activate his sunblade then he'd sheath it and we'd open our eyes and brush the vampire-dust off ourselves...
I lost count of the number of vampires we offed in one night alone using that tactic.