If anyone thinks BD-5's OP, here are some fears and flaws.

[b][color=wheat]Fears & Flaws[/color][/b]

As stated before, BD-5 is a very selfish being. Even Anna had trouble reaching past that and become it's only special person. It's a true miser, wanting money and usually only money. If it doesn't get what it wants, which is usually credits, it will destroy any who stand in it's way. This flaw has worsened into ludicrous levels after the death of Anna, the calm mediator which kept it together. It will never save anyone else for the sake of it's own skin and is the worse droid you could pick for a team.

Having friends, colleagues or even partners scares BD-5. It's precious connection with Anna was it's first experience in the matter and the last. It fears what would happen if it ever gets that close to anyone that close ever again. This is one of the multitude of reasons as to why it hates being in a team. If it isn't working together with people for mutual survival, it will usually avoid crowds of people and teamwork.

It's biggest physical flaw is it's speed. This is the biggest flaw in it's design and is the one BD-5 is most conscious and worried about. It's top heavy structure and slightly disproportionate legs doesn't make running any easy. The sacrifice of speed for immense strength may have been what the scientists were going for but it still pains the droid when it needs to escape from a situation. 

There is also a structural flaw in it's design. BD-5 has a very complex and powerful engine core that is surrounded by advanced but frail coding and data storage. The chips can break easily and if exposed to any corrosive liquids or even water for an extended period of time, they short circuit and break. It's engine core runs on a special type of plasma that is highly volatile. However, it is located in the droid's chest plate, safely burrowed under metal. But there is a weak point in it's lower back where a hastily designed cooling system is kept to keep the core and storage at a good temperature. If hit, the data storage will no doubt be destroyed and engine core explode. The explosion will take anyone within a ten meter radius.