Stop panicking, there are some good things about preseason.
The boards have been exploding over the preseason changes, in under 24 hours. Mostly about a certain ferocity passive, but with the undertones of this game turning into "League of Snowballs" or mages being more useless as a midlaner than as support with 
. While the multiple threads on 
and
definitely hold weight, and mages seem to be getting kicked in the shins, remember this Its Preseason.
-
Not everything is gonna be perfect, and while some things like the damage of  and should definitely get tuned, not everything needs to be nerfed on sight. Afterall, many curious cats are playing squishies who can't absorb constant crits well. -
Look at all the amazing things Riot has done for you guys...
New Champion select that alleviates some rage you get from being forced into a role you don't want.
Amazing reworks/tuning of marksman that makes them fun and unique, you'll never find 
, 
, or
to feel boring to play as they all have new ways of doing damage (from a standpoint of regardless whether that damage is too much ahem )
Masteries that made you think, that are interesting, that get the mind turning ( I know I did especially when i realized all the different 18-12 combinations for different champs). And while some masteries definitely seem more powerful, or the fact that you can't go full 30 in one tree may be disheartening, its definitely a new way to specialize your champs(plus it is more intuitive for new players)
Finally, the item changes and additions at least make adc itemization far more interesting than before, whether or not certain items should be tuned back to a more binary role for others (
)
Tl:dr Don't panic, don't cuss out Riot, give it a week, at the least, to form an opinion. Do not hiss at bad, revel in the good. Afterall, some champions are just Ok the way they are in the League of Adcs.