So, it felt wrong that the only review regarding Calvin was a negative one. As I'm writing this Dark Side of the Moon is the most recent pack and boy has Calvin gained a lot since his release back in the Forgotten Age.
Let me start off by saying: no, he is not the most powerful investigator in the game, probably not the strongest survivor either. But he is by no means weak or underpowered. His playstyle and strategy are very different, but he's a totally serviceable investigator.
In general, you should try to push the risk/reward with him: while you can use "Look what I found!" and Flashlight to get clues and Fire Axe to kill enemies without stats, Calvin is really at his best once he's got a 4-4-4-4 statline. With Cherished Keepsake and Leather Coat you can avoid getting killed, with Peter Sylvestre and the new Jessica Hyde acting as more powerful versions that take up an ally slot. If you want an ally that helps with your economy, Madame Labranche is perfectly fine with her 2/2 soak.
I think a lot of the tools I associate with Calvin appeared in The Circle Undone or later, leading to a lukewarm reception upon his first arrival. Cards like Meat Cleaver and "I've had worse…" are great, not to mention Five of Pentacles or Trial by Fire, two cards I think really push Calvin to the next level.
I find Calvin performs best in a flexible role that focuses more on enemy management but can get clues in a pinch. Survivor doesn't have a ton of clue acceleration and he's got access to some great weapons. Cough, Meat Cleaver, cough.
For his Spirit cards, please don't underestimate the value of these. Ward of Protection and Ward of Protection, Stand Together, "I've had worse…", Heroic Rescue, with Dream-Eaters also giving us Self-Sacrifice and Solemn Vow.
So, yeah. If you aren't sold on Calvin Wright, give him a shot. He might surprise you.