Why are players complaining about the new Ryze concept?

I'm not talking about the current numbers balance on the kit but more about the concept in general. I searched the last weeks Ryze posts and there's a lot of complaints about him not being tanky enough, mana not being beneficial enough, not being consistent damage wise, etc. but I just don't get it. all that stuff can be tweaked to balanced.

I personally think RIOT's current concept is awesome...

1. Through the new passive, RIOT created windows of opportunity for Ryze that are somewhat manageable for the player. At least more than with Gnar's transformation.
2. They allow opponents to see where he is with his stacks so they can tell when to engage... or just shut him down with CC... or disengage for a few seconds.
3. The above combined with the new Q skill shot makes him much more fun and challenging both to play and play against.
4. Like Rumble, passive management will differentiate the good players from the great ones.

The kit numbers can be tweaked until they are balanced but you gotta admit his current kit is weighing him down. Riot can't buff him to a good spot with how he's currently designed while the new kit gives much more wiggle room that way. Am I that wrong???

P.S. But I do hope they keep him as a bruiser and not make him too squishy or being ganked without your passive ready will be a death sentence.