Risk is a game that I’ve only played once, but I found an online version to play for free (ad supported).
So, here are some of the things I think are wrong with the game.
1. Rolling the dice. Risk is painted like a strategy game, but in many ways it is mostly about chance. Even a small army can defeat a big army with a lucky roll. If the opponent has one soldier against 20, he can still win if he keeps rolling a six. Which can be frustrating.
2. Balance of the game. The game gets bigger as the game progresses. So that means it starts off pretty slow and conservative (usually) and then it gets going. Maybe this isn’t a bad thing. Many games will do this and start off slow and then get more interesting. Some would argue it’s better to have more symmetric play. This is kind of like how it is in Monopoly. The game gets bigger as the game progresses which can make it frustrating for the player who has very little territory.
3. Reinforcement phase. The more territories you have the more chances for winning you have. Again because a player can win with just one army doesn’t mean it is very likely to happen. So the players who takes the advantage in the beginning will likely maintain the advantage and win the game.
4. Deployment phase. This is at the beginning of the game the player who places his armies first gets a slight advantage. Perhaps this should be randomized somehow. Or there could be rules where the territory you try to get must be adjacent to your other territories. Though that would seem kind of hard to do, and since you are going turn by turn there may be some unfairness if you are going for a higher number of territories to occupy which gives you a big advantage.
Other than that, i don’t see too much wrong with the game as it is a very simple game. The randomness I argue does balance out the leading player’s advantage. I really like risk, but I can see why it can be frustrating.