I am wondering, in tight deadlines, who has time to implement design patterns? It is a lot more work and programming overhead to get it right the first time and within time frame. I know that it has long term advantages, but were you able to implement any design pattern correctly when the client is sitting on your head and pressure is growing.
I think once your first version is released and you have plenty of time for the next release, than you can think of improving code quality and manageability with design patterns.