Poor Rohgaah, despite a flavorful mechanic, and being the cover of Scrye #1, he's disliked. In fact, InQuest once called him 'the Worst Legend of all time', he permanently sits at a rating of 2.5 start out of 5 on Gatherer, and the comment section shows that to well.
|Well it also has 'Spellfire' on the cover, so maybe not the best endorsement.|
However, if I may argue, he has one new quality that he hasn't had in the past, he's now also a Kobold.
Yes that little tribe that couldn't, the tribe more famous as a combo piece in a jank legacy deck and a running joke (+0/+1 and trample, first strike on 0/1), then an actual tribe, and fan favorite to players everywhere.
Sure Goblins and Orcs are easily more consistent, more prolific, and even dwarves could be argued to be better in the format. However, Kolbolds, have not 1, but 3 0/1 red creatures for 0 mana, as well as three decent lords, two of which give abilities (first strike and trample).
So why the bad rap on this guy? Well, he only pumps the Kobolds he lords over 'Kobolds of Kher Keep', and he demands a tribute of 3 mana, or him and his buddies are defecting to greener pastures.
However, thanks to him, two cards have been printed this century that specifically make Kobolds of Kher Keep. Now, a black 5/5 for 6 with an even situational lord effect is definitely good, though he could use some form of evasion.
However, as said, in times before the grand creature type update, he never got bonuses, from the Overlord, the sergeant, or the task master. He now gets these bonuses, as minute as they may be. So in theory, he can be a 5/6 trampling first striker giving two of your other creatures +2/+2.
Then he's perfect for flavor. Unlike some other tribal/flavor decks in the format, you can use him to amazing effect, and he makes sense, and if you aren't playing a Legend legend in your 93/94 deck, shame on you.
Finally, black/red isn't a bad color combination, sure it's hard for the enchantment removal, but hell, run some discs. Include Ashnods Alters, and his small guys for a massive Howl from Beyond (or a massive damage), or include white, so you can run Army of Allah to help those little kobolds as well.
In reality, in a era of Yargle, niche edh commanders, and well, stuff, I can't say he's the worst Legend in the game, especially since he now has tribal synergy, he makes a great 'Champion' for your meager Kobold deck. Plus if you were worried about winning, you wouldn't be reading this!