Well, we can all argue personal opinion, but I think someone should at least note that the Queen has the lowest win percentage of any DG (Beast has the highest). So all things equal, that is a pretty decent indicator.
My anecdotes with her generally involve her simply being unable to pull her weight in a game. She has no stopping power, ground spikes and spike wave are really not good enough abilities, especially against opponents with some armor on, and scale terribly. Level 4 Ground spikes does 675 damage in an area, and is pretty much the worse AoE spell in the game because of it. It won't even kill upgraded priest grunts. Spike Wave is an awful boulder roll.
Shield starts off nicely, but as any Sedna player who has tried to play her without pounce knows, you need some teeth with your healing, or you just aren't effetive in 2v2's or greater.
The only thing the Queen can do truly well is kill buildings. Ground Spikes is an amazing tower killer, due to towers having low armor (if any?) but I think as the player base is getting stronger, towers are becoming less and less of a threat in general. Unless you are playing Fortresses, I think this ability is not good enough.