It's a competition. Not everyone gets a prize. Wolf collars were introduced so people who participated in a season but did not place Top100 got a reward too. There are 4 different colored Hellhounds already. Do you know the circle of rewards for Feast? 2 consecutive seasons offer the same reward with the second one being recolored/slightly different. If you put the same reward in another season, I can already hear people crying over people placing Top100 who already got the reward from a previous season.
Those rewards not only represent that you made it to Top100. Those rewards also represent each season. So bringing them into another season is just...
If you're asking for Hellhound being released outside of Feast one year later then please look up my first post or my first sentence here.
The class balancing as of right now is pretty good and you see every class being played in top tiers.
There's one thing I agree on with non-Feast-people and that's Feast rewards should have no relations to PvE. I know Hellhound was highly requested by the PvE community and putting it into The Feast was not a good idea. Same goes for the Magitek Conveyor (the flying seat from the scientist in Ala Mhigo dungeon). I guess SE tried to make people play Feast but imo it was not a smart decision. I would have liked to see Hellhounds being the current primal mounts and the wolves as Feast rewards since Feast is wolf themed. But SE decided otherwise, probably because the wolf mounts are Okami style and match the whole eastern theme SB has.