I do not think this card is good at all. In fact, I bet it won't even get much play is Limited.
It is too slow to be useful for an aggressive goblin deck. And the fact that you have to attack with (at least) all your goblins every turn makes it useless for R/X control decks.
The only real use I can think of for this is with a sac outlet that isn't too timing dependent.
While Double Cleave is situationally better, and certainly not a bad card, I think it's clear why Berserk is better; the trample is critical for it's effect. If you are able to sneak one unblocked creature through, chances are it's going to be your smallest, making Double Cleave's effect much less than Berserk's would be.
If I was running a deck where I had a choice to play either and manabase didn't matter, I would give the slot to Berserk every time. Luckily, that isn't the case, so Double Cleave has plenty of opportunities.
An Archon, in its most techincal sense, is a high official in an organization, particularly a religious one (see Cabal Archon). It is also used in some fantasy settings to refer to celestial or angelic creatures. Since the figure riding the lion-creature (which I would assume is a Lammasu) is a humanoid male, I'm going to assume that an Archon is a creature type for a male angel.
It is too slow to be useful for an aggressive goblin deck. And the fact that you have to attack with (at least) all your goblins every turn makes it useless for R/X control decks.
The only real use I can think of for this is with a sac outlet that isn't too timing dependent.
If I was running a deck where I had a choice to play either and manabase didn't matter, I would give the slot to Berserk every time. Luckily, that isn't the case, so Double Cleave has plenty of opportunities.