ana I think we have greater influence on the EU than the right wing media give us credit for.
With regard to treaty changes, to the 4 basic tenants - this is what they are largely banging on about. Of course if you change these to say for example stop free movement of people, it would negate the entire idea of a single market, as it would put it entirely out of balance.
With regard to other changes in EU law. The U.K. Can along with other nations suggest new or altered changes, which will be presented to Parliament and voted on. If the UK strongly objects to a particular issue is does of course have a veto and can opt out as it has done a number of times. With other areas like the "bent banana" syndrome. This is a happy little game many of the Brexiters like to play, but it bears no comparison to reality.
The most important issue I think with regard to the EU is that the UK's strength does have a balancing and influential effect on the whole of Europe. Our culture and history can bear down on the development of EU law. This together with a balance to German influence and strength is essential in the health of the EU. And Europe as a whole.
The question of what we pay to the EU is another area of contention. What the Brexiters fail to understand is the concept of the single market, which given their background is somewhat surprising.
This then must be looked at as a single unit of trade. The participants set up VAT collection and pay a levy to a central bank. This is then distributed according to agreed need. The idea is to develop and expand markets in all the areas of the EU particularly the poorer areas, in order to provide businesses in all EU countries the advantage of developing their businesses. The idea is to eventually bring these poorer nations to a level equal to the rest and thereby provide a healthy and thriving market.
Clearly it is a concept we in the UK are very familiar with, as it has been applied since 1947, we pay in to a central point and take out when needed. We hope that we never do need it like health and unemployment, but understand the concept nevertheless.
Some areas of industry are seen as important to the EU as a whole -the need to feed ourselves for example, and these have been given special attention.