Few people doubt that the current generation of GM foods are probably safe to eat and probably don't cause massive environmental harm.
Please tell that to pretty much every anti-GMO group in existence. No one is saying that there aren't social issues or potential unintended consequences. With every new technology, from fire to the printing press to the internet to genetic engineering has that potential. But make no mistake, the vast, vast majority of people out there who dislike GE crops claim that they are dangerous. Just look at the Slashdot discussion of the study claiming they caused organ abnormalities for proof of that, or simply Google the term GMO for plenty of people claiming that genetic engineering is, somehow, dangerous. You might be concerned with more science based concerns, but most people aren't.
As for the questions you pose,
- Can we rely on the integrity of the people who will test the next generation of crops and do we have sufficient controls in place to prevent biased testing
That is not exclusive to GE. Obviously, we need strong, yet not overly restrictive, regulation. AS it currently stands, I'd say this is a yes.
- Are the risks of GM food - however small they may be - borne by the people who profit from the technology? If not, how do we address this fundamental disconnect?
That's an interesting question, one I've never really thought about and don't really have an answer for. Assuming there is any risk, who is to say what the developers eat? Again, you could ask much the same about many things. The scientists I've talked to eat the same food as everyone else though.
- What are the long term risks of reducing genetic diversity amongst our food crops? Does it make us more vulnerable to unexpected, intercontinental crop failures or reduce our ability to cope with climate change?
Reducing crop diversity does this, but you bet the question here by assuming that what you grow is dependent on a particular technique for plant improvement. GE does not decrease crop biodiversity. If anything, it is conventional breeding that selected for or against the genes that left us with what is used today, not the insertion of a few transgenes. Biodiversity is extremely important, probably more important than genetic engineering, and it is pretty crazy how many neglected crop species there are out there (teff, sorghum, quinoa, amaranth, fonio, sago, ensete, oca, sunchoke, mashua, yacon, jicama, maca, screw pine, breadfruit, jujube, pawpaw, goumi, che, maypop, jabuticaba, acara boi, cupuaçu, ugni, quandong, zabala, naranjilla, cassabanana, yellowhorn, melinjo, chaya, salicornia, katuk, New Zealand spinach, Malabar spinach, corn salad, ect ad nauseum to name just a few) but it remains a separate issue, and genetic engineering is not impeeding these species in any way. What, I ask, would you call introducing new genes into what you grow? That's increasing biodiversity, and it is also what genetic engineering does. GE works on the same principle as increasing biodiversity does.
- What are the social, economic and geopolitical consequences of making third world farmers dependendend on multinational companies?
Nothing good, and you'll be hard pressed to find anyone say otherwise. Fortunately, that is not the only option. For projects like Golden Rice and BioCassava, among others, farmers would be able to save their seed (or cuttings in BioCassava's case)as they see fit. While those have yet yo be released, even Monsanto lets farmers in developing countries save their seed, IIRC, provided they make less than $10,000 a year.
- What are the social, economic and geopolitical consequences of the planet's primary food sources being subject to patent controls?
So far, not much. You also assume that all GE crops are under patent. This need not be true, although presently there are no open source GE crops on the market, and thanks to regulatory hurdles, that will not change for a very long time unfortunately (there is however the university produced Rainbow papaya which I hope will serve as a model for future university produced GE crops).