next new champion?

Mordekaiser on PBE, check him out

They need more hybrid items as well

Hybrid champions have a lot of issues. I don't think a good one could me made in the current state of the game. Probably could in a year or two.

Hybrid never really works well in League since typically the ratios or playstyle will normally swing one way causing you to heavily prefer AD (Jax/Irelia) or AP (Akali/Katarina). The other outcome is the Hybrid causes you to benefit WAY too much from it and be crazy overpowered due to the passives/ratios that promote hybrid play (Old Jax with the large health pool and Old Kayle who got absurd AD and AP off of Gunblade). If Riot wants Hybrid to be a thing they will probably touch on it after Marksman which gets item changes after these Juggernaut changes but will probably treat it like the Juggernauts and do some "reworking" alongside it for Jax, Akali, Kayle, Irelia, Kat, etc. before they even make another champion like this.

Hybrid Items will probably get touched on in preseason though since it's been a long time since any of the items have been touched (Gunblade getting an AP Scaling on the active is the last change I can recall) and Rageblade really needs all the help it can get.

TL;DR: Hybrid Items and current "Hybrid" Champions will need to be addressed first before another Hybrid Champion can be introduced.

Hybrids have crappy lategame.