[DavidG]

Just My 2 cents worth based on a multi-player game that is at about turn 100:

The Federation is way too powerfull! I think the combination of the Fed Sensor array and their training facilities (which can take ships to 25% very quickly) makes them uber powerfull. Compare this to the Romulans who can only train to 12% and have no equivalent to the fed sensor array. In ships with similar level of tech this results in the Feds having a 58% advantage in combat. This makes them pretty tough to beat. I think the fed sensor arrays benefits should be much lower. (even if it gave say a 5% combat bonus it would be a usefull componet due to it's long range scanning ability)
IMHO the training facilites need to be balanced out a bit. I think it is one of SE4's major failings that training is so important. Personally I would like to see the maximum levels reduced and the training speed slowed down.
Also I think warrior races like the Klingons and Romulans should be able to train a bit (just a bit) higher than the Federation.

Also I think the maximum trade level is too high. I know this is easily changed and I plan to for our next multi game. I think the trade level also benefits the Feds assuming you are role playing the race. A race like the Borg or Romulans doesn't have a hope of beating the feds since they would likely shun all traties.

P.S. these opinions are all based on the assumption you are playing an all human game.