Very good card and as stated above it is a better version of firelands portal since the return is guaranteed. I cannot tell you how many times I have spawned a bomb squad off a firelands portal, it feels terrible.
It seems like blizzard is determined to make the elemental tribe actually powerful and not a gimmick like the grimy goons.
I dont get why this is so forced or unoriginal. Other minion types (dragons, mechs, pirates, murlocs ) have even more boring effects and are just buffs or things like just damage (exceptions being finja, parches and a couple more, but they are legendary so....) and no one complained. This is very strong in elemental decks and Will be played even in decks that normally run a couple of elementals (shamans and maybe mages)