I've never had any complaints about hitting the cervix which I know I do regularly. In fact, I've been told how good it feels to her. In most positions, the head of my cock just flicks it as it goes in and out. I'm nowhere near as long as alot of the guys here but in some positions, my cock goes in deeper past her cervix and presses against the top end of her vagina. This will cause her pain. That may be what a lot of you well hung guys are doing.
Even though I did recommend for a guy to angle deep thrust behind the cervix and into the posterior fornix, I do believe that the guy could still cause the woman discomfort by going to deep even in the fornix. I also believe that some women confuse the pain of the penis pressing too far into the end of the vagina, into the fornix, for the pain of being hit in the cervix. I can remember reading threads on forums where I was sure that this was the case. If they are missing the cervix, and discomfort is still caused by going too deep, they are basically going too deep into the end of the vagina period.
While some women do enjoy it when a man pushes into the end of the vagina, the posterior fornix, not all of them do. And of those that do different amounts of pressure is prefered. Also, the timing of her monthly cycle can affect her desire for having the end pressed. Last, some women don't like much pressue until orgasm, then a light deep pressure or gentle deep rubbing really sets them off. Not jamming deep, but just slightly pushing the limit.
You long guys will just have to communicate well with the woman and find out what suits her best. Be jentle, and try different depths at different times, but remember to follow the rear wall of the vagina to go in the deepest.