I've definitely thought this as well. Yes, positioning for us fellas can be a tricky arrangement whereas women don't really need to worry about positioning as much, if at all. Being a seasoned pro at diapering up, I've been wearing diapers on and off for 12 years and I've been wearing them at least once or twice a week for the past 5 years, I can safely say that I've gotten positioning down to a science. There are two positions that work, pointed up and pointed down. I prefer pointed up because it prolongs the use of the diaper and makes the saturation more even.
The one thing that is always difficult being a male is as you said, when things get bigger down there. The down stairs area is very sensitive, it can get going with very little physical sensation/stimulation and nothing sucks you out of little mode quite as much as an unwanted hard-on. Fortunately, I've gotten desensitized to this over time, I don't get excited down there as frequently anymore, nowadays I only really get excited down there when I am first taped into a fresh diaper and even that isn't a sure thing anymore. Of course, being a predominantly nonsexual AB (which I am) helps in curbing that excitement a lot.
So, in answer to your question, yes, sometimes it can be annoying and tricky diapering up and wetting with a willy between your legs and this is an issue reserved for us guys, though, I think it's safe to say that the women in this community likely have their own troubles/problems when it comes to padding up. However, as I said, if you tape up and have it in the right position, it's not so bad and the more you wear the less likely you'll be to get stimulated down there... at least, this has been the case for me anyhow. Also, since I found the proper positions through years of use, pointed up or pointed down, I rarely ever leak. The last time I leaked was about a few years ago now.