Let's not jumped to that conclusion, shall we?
Also skimmed the article, I only found this phrase where he indicate what makes the game repetitive.
Don’t get me wrong; when you fight each colossal boss for the first time it feels incredibly satisfying finding its attack patterns and weaknesses, but it’s when they use that same boss as the basis for multiple missions that it becomes concerning.
Well the only I could said its: This is a first generation game, are you expecting this to have the same amount as MH3U did? While what Ridley have said it's true that lack of content will make the repetition feel come sooner, expecting the amount of content where a hunting action game have different monster for its main quest in the first generation isn't fair. If the reviewer acknowledge this (lack of unique content, specifying it being the number of monters species) and bring up hard fact with comparing it to the first MonHun which have 17 monsters (including 3 online only monster I think), I can accept the argument, as Toukiden only have 12 onis (recolored sub species don't count I think).