1. It is called naval idea points exploit, and it is gamey tactic. In most MP games it is forbidden.
1) I do NOT, repeat NOT, play MP, so why shall I care? In more, it is not free, as I stated you loose Victory point, so it imply you to take more province to get a good peace (or make war longuer, both options that can be harmfull). My advice was : do it 2 or 3 times max time to regroup the french fleet (exemple). that being historically exact, corresponding to the only 2 defeats Nelson got during that career(2 minor battles, where Latouche Trville went out to harass Nelson, in 1803 or 1802 I believe). used heavily with galey is obviously a 'no fun' tactic.
2. Economic ideas? I think it is poor choice , when you can take ideas boosting your troops.
2) I did not , repeat not, discarded those ideas, I did even named 2 of them, still in SP and playing France, taken the economic ideas (the first 2) will boost your money and will allow you to improve your internal strucutre, get more troops (and more money, so improve more regions). To say in 1808, I do cash 350 $ each month (so every 3 month I upgrade a province).It is a narrow, less walked path , that may or may not be of value for some people.
3. Money is usually not problem, with current loan/peace system. So losing ships not hurts player too much. Maybe with full blockade when WE is issue, but AI don't do this...