The game generates enough really impressive newgens that editing isn't really necessary at all.
A favorite trick of mine over the past few versions is to have the MLS running as a full league on any new game I start. There is then a batch of first-day newgens created. On past versions, they would be American (occassionally Canadian or Mexican) and often MLS Draft protected, but there would often be one or two with really high PA (170-plus). Sometimes more. On FM15, the same thing happens but its better - they are never MLS Draft protected and some will have EU nationalities. Not just as second nationalities but often as the primary. It seems like it may be linked to the leagues you are running, but I've seen lots of English, German, French, Brazilian, Argentinian, and similar. Easiest way to find them is to use a scouting tool right at the start - if you are a club of any size, you can sign them to Hot Prospect contracts for no compensation and if they are at least 18 years old, they arrive immediately. You can also just spend time looking through the amateur clubs in the US and scouting ones that look interesting.
Case in point - a game I recently started had two remarkably similar newgens created. Both had CA of 100 and PA of 200. Both were 18 with very good Professionalism, Ambition, and Determination. One was an American striker and the other was a German/Albanian DM. Not perfect stats for their respective positions but both very likely to develop into world class players.
Although to have 2 with PA that high doesn't happen frequently with MLS first-day newgens, its not a total anomaly. A game I started last night had an 18 year old French striker with 198 PA. A Fulham gave recently gave me England's #1 of the future. A game with a Prem club that has no real youth development to speak of gave me about 8 players of PA 140-plus who I signed right at the very start to stock the reserves with good prospects.
The game typically seems to generate high potential newgens with CAs in the 80-110 range, with the occassional one showing up with a CA of up to 125. Outside of the first-day batch, newgens are often 15 and 16 years old and oftenhave CA in that 80-110 range. Given that a fringe top division player in a top league is going to be about 120-130 CA, with someone in the 140 area being a likely solid starter, you can definitely find young players who can make an immediate impact. With high potential, good personality, and good facilities, they can develop rapidly with even an AI club. Which is how you see ridiculous looking 16 and 17 year olds.