From the "Something to consider..." department:
I can't speak for PADI (since I don't know their requirements at all) but SOME levels of dive certification should be carefully considered before one pursues them.
Why? Because your legal obligations change when you move from the "amateuer" to "professional" ranks with regard to assisting other divers in peril/distress.
As it was explained to me, as a diving professional I have an obligation that differs from your typical recreational diver to assist and render aid...
This difference doesn't change how I'd personally react out of a moral sense, as I'd like to think my actions would be the same whether I carry a "professional" card or not. However, it does appear to obligate me from a legal perspective, which is an important distinction.
Let's say, for instance, that I am diving on vacation in the Caribbean, and while I'm on a dive, another diver that is a stranger to me and that I'm not even diving with has an accident. Because I am an instructor, I have been told to expect that lawyers will come after me, even if I wasn't anywhere near the site of the accident.
Now, whether or not such a lawsuit has any merit isn't the subject of this discussion - the subject is whether or not someone might try to bring litigation against me, and I was told by two different Course Directors that there is a history of exactly that.
As a result of being a dive professional, I carry a couple of million dollars in insurance, which is designed to protect me in a few ways which aren't germaine to this topic (and which costs me a few hundred bucks every year to boot).
But the point is this: before you take on the responsibilities of professional dive leadership (which may or may not be involved in the PADI DM program), I'd encourage you to research the liability aspects of it, and more than ANYTHING else, make certain you are engaging in such a program for reasons that are really important to you... reasons like helping your fellow divers explore our ocean planet to its fullest!
Anyway - I guess the idea that I'm trying to convey (poorly) is that a "professional" card carries with it a different set of obligations than a Night Diving or AOW certification would. For me, the rewards of teaching diving are absolutely worth any legal risks involved, but I just wanna make sure people go into such roles with their eyes open.
Being a "pro" doesn't make me a better diver (necessarily), but it does bring with it some hefty responsibilities that I am glad to bear. Make certain, as you continue your diving education, that you have a clear understanding of what those responsibilities entail.
-david