Ryze the newly tanky rogue mage. I never enjoyed playing Ryze before his transformation due to his extreme squishiness, extremely long cooldowns, and lack of reliability in team fights. Some people say that his transformation has been nerfed, however, I think it opens new doors for Ryze. In my discovery, Ryze makes a perfect tank. Why would I say he makes a great tank? Well, don't worry. After my explanation, it makes perfect sense for Ryze to be a nice ap/tank.

1. Ryze is now a magic machine gun, his damage ratio may have decreased, but with his lovely cooldown reduction passive, he can do continuous damage over and over and over again. No need for AP anymore right?
2. To prevent Ryze from being targeted so desperately, it is imperative to add some armor, mag res, and health, so he can stay in the battle much longer, meaning more experience, more reliability. Remember, I want to be in the battle as long as possible only to go back to base to shop.
3. Tank Ryze makes him perfect to initiate a fight, performing non stop snares and CC. His ult allows him to damage multiple enemies in team fights, while draining HP from those squishies.

Pros
Perfect support, initiator, and magic damage dealer
nonstop continuous damage for as long as his Mana lasts
Useful snare for trapping or escaping
Useful ult to restore HP
Great armor, HP, and decent nonstop damage.
Can most definitely destroy AP Ryze, and every other squishy
FUN TO PLAY!!!


Cons
No longer a nuke as he used to be (But now his transformation no longer makes him a nuke)
Now focused even more
Mana dependent early game
Slightly team dependent

After looking into his role in the game, I feel imo as well as all my other buddies, that his Pros as tank ryze most definitely overpowers his cons.

His runes will be magic Penetration and defense and mag resist.
Magic penetration runes really do help spamming overload. And the defense and Magic resist runes help you stay longer in lane early game.

You want to max out Overload (q) as fast as you can. It will be your "go to" skill. Maxing out q will do good penetration damage to your enemy while also reducing the cooldown for each of your spells by 1 second. That's just awesome in my opinion. I want to keep using Rune prison as much as I can so that not only I can do combos, but my teammates to start doing damage as well. As I said before, the purpose of Tank Ryze is to initiate the fight and deal damage.

Buy sapphire crystal, 1 health pot, and 1 mana pot. Either run mid, top, or bot, you are most likely to dominate in each lane. Use your mana wisely, as you are short on mana, but sapphire crystal will help you stay in the fight longer. Keep your enemies away from you. And harass with your overload as much as possible. Get Frozen heart immediately while getting mag pen shoes in between.

So basically everyone is now at mid now, and most of your team are either dps, casters, and/or squishy. Your job is to catch one of your enemies from being either to close to your team, or too far from their team. When you find an enemy off position, Overload, Snare, Spell Flux, Desperate power, overload, and snare again. The skill sequence in this order, will help your team dramatically and give your teammates more than enough time to take the kill, if not, you :D !!!!

Now, both of your and enemies' turrents are down, and its a neck and neck battle. Maintain your cool stay alive, because your team is depending on you to start the fight. Rush to the enemies base harass and slowly pick off each team 1 by 1. You should now have so much health, with armor and mag resist, you are unlikely to die, and you have a sh!t load of mana to keep casting your spells. Hurry to the enemies base with your teammates behind you and finish the game. Trust me, your team will thank you.

I tested this build myself, I went positive in every game keeping 10 or so kills for myself. :)
It works for me. I like having ryze not squishy. Don't you? Let me know if it works for you. If not, downvote me because I wouldn't care. But I'm just here to help. Have fun!