[TCPLemminks]

According to Day[j], one can only support a 4 gate for 1:30 in game minutes...
The proposed patch probably means you can get out 1-3 extra units before the warp gates are done, since you'll mayeb have time to get a unit out of your 3 gateways that should be done before warpgate finishes.
However i think that if they do add the reduced build time for training, you could probably have an extra cycle or two worth of units out before the 4 gate is ready. Not 100% sure on my maths though. So 4 gate may still exist, just with more units on either side