From Alex Ich himself, answering the question "Which champions do you consider strong / OP on the live patch, and why?"
It doesn't get much clearer than that. Ryze is just pure bad and moronic design, as most recommended champions tend to be. Completely opposite to what WithoutQuestion wrongly said, Ryze is never truly shutdown. He is always a threat. Like the OP said, I've been there countless times: games where i'm completely stomped in the lanning phase, but by simply farming sufficiently and being at teamfights, I eventually get the few required items to be an imminent danger. And that ultimate... how many times have I baited people into trying to kill me when seemingly low on HP, only to have spellvamp turn the fight completely around.
Also, Muramana... that is all.
Oh and though you are absolutely free to disregard my opinion, it's worth what it is (which may very well be nothing), please note that first part is coming from the Alex Ich, someone who knows and will most likely always know much more than you and me about League of Legends.