Well actually it's not just a direct comparison to HH, it IS also a pretty beloved feature for the average MMO, not even for RPGs, it goes from Adventure Quest Worlds, to CLUB PENGUIN even. Helmet Heroes just did it the best, it made pets both cute lil monster dudes who follow you, helpful "auto grinders", and not to mention the stat boosts, now that was what made pets extremely worthwhile.
Essentially, don't immediately say additions like pets or accessories are directly related to Helmet Heroes, or that we don't "need" em as if it's exclusive to HH. Considering the mountable scorpions, I'm betting that pets will eventually be added. I mean it's a feature that BUILT the economy, why wouldn't robby add em again? He could even improve on em by adding nifty features such as sitting, arguably something that would make grinding pets as a warrior WAY less tedious, trust me, I would know.