It can be very difficult in judging players who are 16 and what they will do once they hit the minor leagues. Lara I believe was a top 5 or top 10 during his signing period. A lot of those guys flame out as it is impossible to tell how a 16-year old is going to pan out when they are signing. Just look at the MLB draft where players are 18+ and how many of the top picks don't even make it past AAA.
Demi always had the power that you fantasize about in a baseball player. The problem he had is that he could never get to that power in a game as he was never able to make enough contact.
Baseball is an extremely hard sport to break into. An injury to your wrist that wouldn't hurt you in the NFL can basically end your career in MLB. It is extremely difficult to make it from HS --> College --> MiLB --> MLB or HS --> MiLB --> MLB. For the players from other countries it is basically Little League --> MiLB --> MLB. A lot of the players are going to just not make it. I think the Brewers saw this and instead of spending all of their money on a few players they decided to go the route of signing as many as you can and hopefully you don't roll snake eyes on all of them.
This is also the time when the Brewers were emphasizing power over all other aspects for hitters when drafting or signing international players. In the previous draft of the Lara signing the Brewers drafted Gatewood, Harrison, Stokes and DeMuth in the first 5 rounds. I believe Stokes was the only one that didn't fit that power profile that the Brewers were going after.