Nooope. There is one reason for this, and one reason only (hint: it's a stat).
Let's analyse the speed of every Dragon Pokemon ever:
80, 85, 90, 95, 97, 98, 100, 102, 110 vs 48
Altaria & Dragonite sit at the lowest (80), followed by Kingdra's 85 (doubled when SS activates, and Rain is going to be more common this gen, so take note of this), then we have four legends with 90 speed (Dialga, Giratina, Reshiram, Zekrom) and two slightly faster legends (Rayquaza, Kyurem) with 95 speed. Our two non-legend dragons this gen (Ononokusu & Hydragon) are slightly faster with 97 and 98 respectively, and then we have Flygon, Salamance and Palkia with 100 speed. Finally, we have the three fastest Dragons of all time with 102 (Garchomp) and 110 (Lati@s).
"WHAT DOES THIS MEANNNN???"
It means Kurimugan is the first NU Dragon of all time. 77/90/90 defenses aren't gonna cut it; even Altaria outclasses this thing, which is just sad.
WHEN ALTARIA OUTCLASSES YOU, YOU KNOW IT IN YOUR HEART YOU ARE DOING SOMETHING WRONG AS A DRAGON. If played right, Altaria can beat this thing, and despite her craptastic offenses, only a fool would choose Kurimugan over Altaria to use in the lower tiers.
I feel so bad for this thing (GF hates it), I can't even express myself properly. Its attack doesn't mean a thing and neither does its defenses; if you're going to be the slowest Dragon OF ALL TIME, you need to have Giratina-esque defenses or you'll be outclassed, outsped and killed by every other Dragon plus anything packing Ice Beam or strong Ice moves, like Skill Link Icicle Spear Cloyster (which WILL kill this thing because it's faster, and Icicle Spear is a dangerously powerful move when used by Cloyster, period).
"Well, there must be something it can do...?"
XD No. At least Altaria has Natural Cure/Cloud Nine, bulk and access to Dragon Dance which works well with said bulk, but this thing can't Dragon Dance, its abilities are meh, and yes, if it hits you, it'll put a dent for sure (120 Attack is great, although almost every other Dragon has it better) but that'll be about it. It will get hit hard, dish out one hit, then get killed.
I don't even hate it; I don't hate any Dragon Pokemon as of date, although most of them definitely don't interest me. But the thing that gets me is just how not good this thing is. It may not be bad compared to Delcatty, but by Dragon standards, this thing is a joke, an abomination, a one leg one arm soldier. XD If those 90 defenses were on his HP and Speed respectively instead of its defenses, it'd have a chance, but as it is? Hell no. XD