Yea, by my definition it is still toxic. But again I think its fair due to being linear and not of really comparable burst or consistency. If you get starhorn low enough on life he just cant do it…unlike the many times I have lost to a reva at one health while I was close to full. Silly arguement or not, its just one more reason why its ok and Gates is not.
Seraphims burst is small and reliant on which side of the board she is on, and or on establishing an answerable board first, both of which you can play around and is again a fraction of the burst potential. Yea Vanar is a touch strong right now, but that is mostly Luminous Charge and Flawless fault, not ghost, and again you can tech to deal with those.
I am also not particularly fond of Phantasm but you have every chance to react to, play around, and make sure you have an answer for it, and its a fringe case it multi buffs a rush minion, tiger is more of an issue then phantasm is. Rush in general can be played around with good positioning, provoke, and nightwatcher, and all rush minions use the board, and have fairly low stats to their mana costs so they are pretty fair, and again a fraction of the burst potential.
There are tons of ways to answer Mechazor, most of which are versatile cards that you ought to include anyways. Titan means your deck is handicapped without spells, is very position focused, and is reliant on developing an answerable field.
Using the board means anything you mentioned, or anything that is position oriented…not being to picky about that. Gates uses none of them.
Powerlevel alone is not the main reason why cards are broken. A faction can have (and pretty much all do) several very powerful cards and not be a problem if they are not dominating the meta, and or there are good ways to play around them. Gates reva is meta relevant, is not linear, and is unacounterable. Its a problem.