There's lots of content, it's just not on the Workshop.
Why isn't this on the downloads site in-game? Probably because the modder didn't post it there but choose to release in on 4shared.
Try
OOTPMods.com - not the most elegant looking site, but lots of content from the major modders of the game.
Also, if you're looking for things like jerseys and caps, many folks have photobucket sites where they store their work. Links are often in sig files.
And the company has now released an August 30th roster update. The game still starts at Opening Day, but the rosters and ratings are accurate as of yesterday. Good for playing "what if Team X had Player Y on their roster all season?" scenarios. There's a thread with a link on the main subforum.