Why leds on ethernet connector are not routed with leds output of ENC28J ?
Are you planning to fix that?
Nothing to fix. The ethernet jack LEDs were replaced by other LEDs on the edge of the board so that all the status LEDs were together. You can always connect the jack LEDs if you really want to, but there's not much reason to do so.
Because i need to put it in the box and connecting the leds via wires looks not so professional...
It's so simple to do that through pcb that i cannot figure out why they didn't
The reason, as stated above, was so that all the status LEDs were in the same place on the board. However, the jack LED connections are there if you really need to use them (and the v2c boards, at least, already have the resistors in place for the jack LEDs). All you need to do is connect them, professionally or otherwise.
It was originally a single sided board and a jack with no LEDs, then when we moved to 2-sided there wasn't a great way to route it without going under the ethernet part of the circuit. Now with the bigger 1.1 board it is probably possible, and I will look into adding a jumper. As dpropicweb said though, we used a single row of LEDs at the front instead of the rear LEDs.