The comparison to Kel’thuzad is all together wrong in my opinion.
KTZ, while still good, isn’t what he used to be. They already nerfed his burst damage and then his Armor reduction. Against a good team, KTZ can’t really one-shot anyone by himself anymore and in return, he didn’t receive more health, range or even reduced his hitbox radius. (Seriously, he has a large hitbox of 1 same as Blaze and Chen, while Muradin has 0.8)
If they are going to further nerf his damage, I expect to see some buffs to his survivability.
Otherwise, he is becoming more of High Risk, Meh Reward.
If anything, comparing KTZ to Orphea, I see those things: he relies more on his combo for delivering damage, doesn’t have mobility, doesn’t have sustain, has same range as her, but he is much squashier (KTZ: 1445 Health, Orphea: 1665), he is fatter and easier to hit by skill-shots… and so on.
When I tried Orphea, I saw better comparison to Chromie than KTZ. Both require to hit enemy heroes with their abilities to empower their basic attacks.
Similar Q: Both have similar delay time and linear projectile. Chromie’s Q has more range but hits only one.
W: Both are pure AoE damage. Chromie’s W has range to it but way more delay time.
E: Both provide some sort of CC.
While Orphea doesn’t have Chromie’s range, she got in return sustain and mobility.
Just a side-note: I’m not making this post to say Orphea is overpowered. On the contrary, I wanted to highlight the problems that other mages such as Chromie and KTZ have, so that maybe they get some attention!