The good thing about the Hunt Caller is that he's a 5/4 for 2GG (2 colorless, 2 Green). Four mana for a 5/4 is solid enough, and his Formidable ability that gives haste can work on himself. Consistently being able to give a creature haste during each of your combats is fairly good. The caveat of total power 8 or more could be a relevant drawback, however. Still, he would be Constructed-playable.
At the time, Red/Green Devotion was the deck that this Surrak made the most sense in. The deck had strong enough creatures that playing a copy or two of this guy wasn't out of the question. The ability to give himself and the deck's other creatures haste is pretty strong. Once Devotion was no longer a thing, he was still strong enough to see some play because of the Formidable ability in aggro Temur decks in which amassing 8 total power was rarely a problem. Abzan Midrange, Bant Aggro, and Temur Aggro were happy to have him around.
Although he's a Legendary Creature, he never really made it as a Commander. On the other hand, he does see some play in other Commander decks. It really isn't hard to get 8 total power on the board in Commander, however. His high initial power and ability to gain haste for himself and other creatures have helped him become useful as a member of the 99 in Commander decks.
All in all, Surrak, the Hunt Caller was a bit underrated during his time in Standard, but lives on as part of some Commander decks today.