The Western Beltway is done going through the resort but I don't believe that the complete road to I-4 has been completed yet. I'm sure somebody more familiar with this will correct me on this if I'm wrong.
As far as making it quicker to Disney, I'm not sure that is the case but it is easier and does avoid traffic lights. The reason I don't necessarily think it's quicker is because you have to travel north for a while, then when you get on Disney's Western Way, you travel southeast and end up on the north side of the Animal Kingdom before you come to the road to head toward the parks. The key is how far north do you have to travel and then backtrack when traveling southeast. I wish when it headed north, on Disney property it would have headed towards the Magic Kingdom. Unquestionably it is easier, I would use this route but as it is now, I'm uncertain whether it is faster.
I think, even with the traffic light, the quickest way most of the time may be to use the East Orange Lake exit, take the left on 192 (heading east), continue to the first stop light (Black Lake Road), take a left, follow Black Lake Road until you come to a stop sign, turn left (onto Sherberth Road), and continue on Sherberth Road until you hit a stop light (used to be a stop sign) and turn right. You are on Disney property. If you had turned left, you would have entered the Animal Kingdom Lodge. You are now on the south side of the Animal Kingdom. If you keep going straight, take the first exit to the right and at the stopsign at the end of the exit ramp, take a left. About 1 mile up is the exit/entrance from/to the Western Way. The only thing that may make the Black Lake/Sherbeth Road method slower is that timing of the stoplights - and they can be long. I hope this helps.