Because Singed kills heroes usual a poison trail behind him. It's an embarrassing way to die. Usual scenario :

1. Newbie sees Singed at half HP and chases him.
2. Singed runs off with his poison trail on.
3. After chasing awhile, newbie notices his HP has gone from full to less than half.
4. Newbie turns back. Singed activates MS boost and chases newbie.
5. Newbie gets tossed by Singed.
6. An ally has been slain.
7. Newbie's teammates starts to question newbie's sexual orientation and parents' marital status.

welp

I'm just waiting to go Lulu + Chogath.

"I'm tanking coz my size is so big they can't click on my teammates!!"

Ryze scales off mana so he is one of the few AP heroes I don't go Deathcap. Early Tear is absolutely necessary, core items would be BV and Frozen Heart. Round it off with Void Staff and WotA (WOTA + the ultimate is OP!).

Agree that Cass and Brand shuts him down early game. But Ryze's early game is his weakest and it's best to be passive until you've farmed up your core items. Cass is seriously good, but has a high skillcap to play. Ahri too. If you want to play AP casters with high skillcaps that are borderline OP, Cass and Ahri says hi.

My other fav AP Mid is Kennen. Devastating in teamfights. And whoever he lanes against, he may not win but he definitely won't lose either. As for AD range mid, I think Caitlyn can be seen going mid in some games as her range allows her to farm and harass most AP casters.

I personally dont think Ryze weak in early game. with low skill cd and good "health support" from ulti. He kind of strongest with 1st blue buff.  Ryze can win a lane easily. Although Ryze cant burst, I believe Ryze had advantage on 1v1 being slightly more tanky and has constant output dmg instead of 1 time burst.

With ulti enabling constant healing from spell vamp. Ryze stays on lane fairly long. *Make use of Ryze passive to refresh the ulti quickly*

Can you guys log in?

Currently training with ryze @_@ its hard to use... But pro use it LIKE A BOSS

Anymore tips dude. Well just to be frank to stay on lane also proves hard for me when using ryze. If I go mid I'll be sure to be overpowered  by all famous mid solo champ like lux, Ahri, kog and etc. Other lane also a bothersome due to lack of ryze in-depth information and play style 

1-6 phase lane for ryze is hell though, most of the time you will be last hitting under turret. for Lux and Ahri, need to try to evade their skill shots , will be beneficial for your lane phase

Once you got catalyst or tear, can start spamming smartcast Q-W-Q-E-R-Q-W-E-Q-W-E (as long as your mana permitted) , Ryze skill scaling with mana more than it scales with AP , so glacial heart or banshee veil is kinda go to item on a hard situation. Finish your tear as ArchAngel last since it is more beneficial for your skill damage scaling that deathcap.

starts with boots + 3 pot if you against ahri or CC ap mid