Well to start with, thank you riot, a character as singed that was in a difficult position with so many counters on toplane has finally become USELESS.
I will explain the reasons.
First of all: You cannot proxy anymore with singed, because there is a hidden patch note that wasn't listed that has made the minions LOSE AGGRO very easily, now they will just run away if you go 3 cm away. Ok goodbye to proxy.
Lets continue, you've empowered mostly all AD champs with the new masteries, this leaves Singed out and empoweres his natural counters and OP toplaners (as if they werent enough overpowered already).
You took his selfsustain (changes to pots and flask) but gave even more selfsustain through masteries to AD champs.
You took away wards, that was a key feature to avoid getting ganked when he was pushing waves hard, or proxing.
You have gave many kinds of movement speed to AD champs, so now running away as singed used to do its getting every day HARDER or even impossible.
Well you could just as well delete him from game...
Most annoying thing is the minions losing aggro so easily, and this WASN'T mentioned on patch notes. I really would like you to make their aggro stay as it was before this patch. Fix this at least please, and give singed some love in next patch (not a single buff to him in this patch, better buff adc's :D )