@Meddler: I really don't think you guys should buff Ryze....not yet at least.
I know his winrate is astonishly low (last I checked it was the lowest). I know people automatically assume this means he's weak or clearly something of a winrate like this suggests he's weak. I'm going to explain why this shouldn't be so heavily considered with reworked champions, so just hear me out guys.
With new champions, when they have extremely low winrates like this it's one of two things: a very complex kit that takes time to learn or is actually very undertuned. Yasuo and Gnar come to mind, having very low winrates upon release and people automatically assumed they were garbage (i was guilty of this with Gnar). It took people time to figure them out but in that time, people figured out playstyles and builds and suddenly, they're overpowrred as all hell because you legit just buffed an extremely strong champion that people hadn't figured out yet.
I know what you're thinking now: what in gods name does this have to do with reworked champions? Well, I'll explain. With reworked champions, in a sense, they're much like new champions because there's a lot of intrigue with them much the same way there is with newly released champions. I'd imagine there's just as much attention paid to a newly released reworked champion as there is with a brand new champion altogether.
Here's where you have to consider reworked champions on a totally different scale. With new champions, there is no reference point. Sure, champion spotlights will included suggested runes, masteries and builds but be honest, how many times have those been dead wrong? Sure they sound good in theory and in the right circumstances those suggested build paths and runes work but this is league where circumstances or so ever changing that it's hard to assume something is law upon new release and that same logic applies to builds, runes and masteries. So while the suggested builds and such are reference points, they aren't very good ones or reliable - they are guesstimations more or less (and that's not to discredit the people who come up with these, it makes sense at the time).
So with reworked champions, you have to consider this: why was the champion reworked in the first place? Typically, it's because the champion has gameplay that riot considers less than desirable and is either bad or stagnant enough that riot considers a small overhaul of their spells or transferring of power as a start. With reworked champions, you have the reference point of how they were once played and built and many people make the tragic mistake of trying to build them the same way as before the teworks (see Sion and how people kept trying to build him full AD). In many cases, this is flawed because typically these builds and play styles are a result of the gameplay riot was trying to remove or change in the first place. In Ryzes case, and this is speculation this isn't something I actually know, riot wanted to remove his power as a top lane bully with point and click harass early that scales into burst and DPS into late while still being insanely durable. This is why riot tries to remove FH from build path or at least make it w's purchase that wastes stats. This is why they made his Q a skill shot (which is what completely broke him in top lane and made him weaker in mid lane) so he'd be less of a lane bully top and now suddenly mid lane looks more attractive. So while Roa and Tear are still core, there's so much that's changed that you have to consider a new build path past those two items, that alone takes a lot of time to figure out.
Then there's this: you have to consider his playstyle and how drastically it was changed. There's no hiding from it, old Ryze was one of the easiest champions in the game with very few decision points (Q off CD? Fire away). His only concerns as a top laner was being pretty squishy and avoiding ganks and when to use Rune prison for disengaging - that was the extent of his difficulty. That changed, oh man did that change in a big way. His passive changed, which is a huge decision point in managing in itself. His ult suddenly gives him more of a spike. His Q is a long range skillshot now as opposed to point and click. I could keep going on but you get the point: his playstyle ha drastically changed. In fact, it's changed so much that I think he's legit one of the hardest champions to play now. The increase in his skillcap is insane, I've never seen this kind of change in a champions play style in my time that also made them super hard to play (Sion was a huge overhaul but he didn't suddenly become super hard to play, just slightly more difficult).
I can't stress this enough, this was such an enormous change on a champion who was previously extremely unhealthy and now yoh could argue he's much healthier but as I noted, much harder. So it was a necessary change. But the point is, I suspect he's actually pretty good, it's just going to take a long time for people to figure all of the above out, which is actually a pretty unprecedented change when you consider reworks in league history (I'm excluding beta here). Give it time, don't buff him now. I think he's much healthier so this isn't me saying this because I don't want Ryze in my games again, it's because I do believe he's strong and if you play this champion, the last thing you want is for riot to keep buffing him when he's actually strong and it turns out they push him way over the edge and they end up nerfing him so hard, he actually becomes weaker than he was perceived to be prior to the buffs in the first place.
As for builds, hey, I'm really a fan of this:

Runes: MS quints, scaling health yellows, spell pen reds, MR blues (scaling/flat depending on match up)
Masteries: 21/9 (9/21 actually doesn't feel bad either).
Some other items that aren't bad:
(good vs heavy AP teams)
(you waste the 20% CDR but the mana and armor is nice against heavy AD teams)
(you don't waste CDR but sheen is kind of meh on him, as is the IBG proc since you don't AA too much on Ryze outside of lane phase; it might be really good though, idk yet)
The build I provided though gives him everything he likes. Mana, HP, damage, pen and spell vamp, which I think he's become an extremely good spell vamp champion. RG is just so good with his ult for chasing targets down as well. WOTA gives him the 10% that caps him out in CDR and it's nice AP and spell vamp, again, that synergies with his ult.
There's also a few other items like
and
that could be built over RG and potentially WOTA (and you could get the remaining CDR from runes and masteries). I love spel vamp Ryze, so it's bias. I think getting 10% CDR from runes and masteries and building Ludens is hella good too.
But do you see what I mean guys? Look at all this shit he can build and the vastly different playstyle patterns he potentially has with these builds now. How can we determine that he needs buffs after such a short time of being reworked so heavily and expect anything good to come of it? Give it a few more patches, I'd say until 5.13 at the very least. I really do think new Ryze is good.
and even