Don't see why they can't add new heroes while buffing the older ones too
I had hoped they would buff old heroes by releasing their skins first, and by making the skins better than they did (like pd's new skin as opposed to all the others which are the equivalent of just 1 trait each..essentially useless). That way old heroes could still be useful, as well as monetized via paid for skins. #opportunity lost
You have to see shard heroes as the first legendaries you'll get. They are much more useful than elites and while they can have a lot of utility late game wise, you will eventually transition to the gem only ones.
In my opinion, no one would care about how "weak" they are if they werent consudered as legendary.
On the other hand, I do belive all gem only herows should be of equal power but the way IGG makes money is via the rolling system and if a hero isn't powerful enough, no one will roll him, so no money. Thats why heroes have and will be scaling in power the newer they are.
More new heroes = more money.
They make them a little stronger each time, to make people feel like they are being "left behind" if they don't have them. Which spurs them to spend more money on the game. And even more, when their initial rolling sessions don't turn out the new hero.
By next year, even Anubis and GS will be getting wimpy.