All of those things, but not next week. New crops need time to be developed and properly tested; it takes time, effort, money, and cannot be rushed.
It will make life easier and more productive for farmers. In the richer countries that will help to keep food prices down; in the poorer ones it will reduce poverty in the communities.
Food will be better because the crops producing it will be less subject to disease and the foods themselves less spoiled by pests. Some foods will be modified to be more nutritious; some will have longer shelf lives, a boon to every consumer, particularly those in poorer areas and countries who may not have good storage facilities.
If we in the UK do not put our heads in the sand, we can expect benefits to begin to flow progressively within a few years. In the USA and Canada, the benefits are already to be had: lower use of pesticides, higher yields and better agronomic practice.
Meantime, much of the Developing World with fundamental food problems, are seeing the benefits already: crops with the potential to solve critical nutritional deficiencies, crops allowing farmers to improve their agriculture beyond mere subsistence and getting a little money in their pockets to begin to move out of poverty. Is that not worth having?
The use of genetically modified crops in developing countries: a follow up discussion paper. Nuffield Council of Bioethics 2004, www.nuffieldbioethics.org
Human Development Report 2001. United Nations Development Programme