I like how Mr Strange explained this topic over here, that Pipeworks’ main release priority is to provide new troops for kingdoms with only 6 troops, and to release troops which were very popular on PC/mobile side. I can attest that early on, back in November, I was certainly looking forward to seeing Hobgoblin while building my first teams.
And we can always use more Beast traitstones (red/green). Eika’s neat List of troops per Arcane stone suggests that Hobgoblin may only need 2 3 of those arcanes to get traited, whereas Salamander, Scarlett, Sylvasi, and GloomLeaf need at least six times as many Beast stones. You’ll be looking for more of these Arcane colours…eventually!