He's decent now. Not *amazing*, but definitely better than he used to be. He is one of the few champs that can both serve as CC and damage - sorta like Elder Skarg.
Unfortunately his A3 being a 4-turn cooldown makes his utility as CC significantly worse - it's unlikely you'd be able to rely on him as CC for doom tower, for example, because while you can probably get around the requirement of burning first before freezing, the 4-turn cooldown on the freeze means its unlikely you can get him to land that same combo on the 2nd wave - and that's putting aside the fact that both his A2 and the freeze part of his A3 are resistable.
Your best bet is probably to have him serve as a backup for both purposes. As an example of a doom tower team he could fit on,
I don't know if I'd actually build him out, but he could be okay depending on who you have to choose from.
I put this in a reply to a comment, but it is useful for anyone wanting to try this. To get the most out of a solo Crypt-King Graal, you need to set up a team so you can prioritize his skills. Set his A2 to opener and his A3 to 1st choice.
The problem this solves is that Graal won't use his A3 on auto unless every enemy already has HP burn. So, if you get resisted on a single enemy, the debuff gets blocked, etc he won't use his A3 which means no crowd control and he's not renewing the HP burns on the champs that do have the debuff. Setting the skill priorities fixes this.
I've called him Trashlord Graal ever since I've pulled him, even though I do use him to freeze spiderlings in my 30 sec S24 team...
But I guess he can't be called Trashlord anymore. Now he's actually going to be really good. AoE HP Burn into AoE freeze, that's super good for PvE, especially FW and DT.
Wish he'd been buffed before I did Undead FW21, he would've made the Valks soooo easy.