Every 4 levels? But a standard fighter gains a new feat every other level, in addition to the normal feat progression of 1 per every 3 levels. Even if these are free bonus feats gained on top of all of that, it's gonna take a long time to gain all of the possible feats with this. Even if an archer took this at 1st level (is that legal? not without skill points, starting gold, etc.), they couldn't use this to gain all of the archery-based feats by 20th level, & they'd be far behind a fighter who just took them as soon as possible. With this system, the temptation to use your normal feats (IE those gained by levels & fighter "class features") for other things would be great, so you'd actually have a build that was far less like what you chose in the first place than a standard fighter of equal level. That's bad design.