Blitz:
I had a bad incident with someone that was "DIR" up here. She was extremely rude. I had no idea what DIR was at the time, but she certainly let me know that my 14 years of diving-several of them as a combat diver in the Army (CDQC) were dangerous and that I had little to no idea what good, safe diving was.
That's unfortunate. Personally, I would think that your military diving experience would make you something of a "natural" with the DIR system. Everything about it is driven by the idea of team unity and putting aside one's personal agenda for the overall benefit of the team and its goals. This is a principle that (in my opinion) is not emphasized that well in a traditional dive training curriculum - in fact, in many cases the "traditional" curriculum engenders exactly the
opposite type of attitude.
I think that people with a military or public safety (fire, police, etc) background probably understand the concept of
true teamwork better than most folks, and would therefore more readily grasp the benefits of DIR.
But I digress ...
Regarding the issue of rudeness - the problems that I have seen with many recent DIR converts is that (1) they don't have the depth of knowledge of the system to fully understand it, or (2) they are not able to articulate the reasons "why we do things the way we do". I think a person really has to do a lot of diving in a lot of different situations to really appreciate the simple utility and flexibility of the DIR gear configuration. Most openwater divers who are just starting out with DIR can't really see the "endpoint" (rebreather dive carrying multiple stages and scooters) and in many cases are simply doing things by rote. When questioned about some philosophical point, they sometimes struggle with an explanation, and then just give up and resort to rudeness. Sometimes I think it happens more out of frustration with themselves than with other divers.
Of course, not everyone who takes a DIR-F course is eventually (or even necessarily) going to be using a rebreather. One of the major benefits of the system is that there is nothing that artificially limits your ability to move forward to those types of dives, other than your own goals and rate of progress as a diver. Everything builds on everything else to create a smooth progression from OW all the way to Rebreather Diver, if that's how far you want to go. In particular, the system is designed such that as you move through the curriculum, you only
add equipment and procedures to your existing knowledge base - nothing ever has to be repurchased or relearned.
There is good and bad to everything. Is it wrong to take the good from one philosophy and combine it with another?
That depends entirely on the philosophy.
DIR is designed to ensure that everything about a dive will work together as a unit - gear, procedures, and personnel. It has been honed and refined over many years and thousands of dives, and represents the collective experience of divers who have been engaged in cutting edge exploration in some of the most challenging situations imagineable (some of whom paid for this knowledge with their lives). It is one of the finest examples of "gestalt" that I have ever seen, and in many cases, changing just one piece of it can have effects on the other pieces that are not terribly obvious at first glance.
I would not necessarily say that it's "wrong" to try and combine parts of DIR with other philosophies, but I definitely believe that it compromises the overall effectiveness of the system as a whole to try and do so. In many cases, it does this to such a degree that it creates a potentially unsafe situation for the diver.
Having said that, I don't think that every diver will (or even can) necessarily turn on DIR like a light. In my own case, I was first exposed to it (as the "Hogarthian" system) in 1994 when I started my cave training. It probably took me two full years before I finally "saw the light" (during which time I wasted a lot of money on some of the most horrific choices about gear that you could possibly imagine). I kept coming back to the elegant simplicity of the whole "DIR" thing, and finally concluded that it was the only way to go. It is unfortunate that so much emotion and drama has become attached to it.
So to answer your question, I don't think it's possible to combine DIR with other philosophies without reducing the overall effectiveness of it. However, if adding DIR elements to your style of diving makes sense to you, then I encourage you to do it. Over time you may find (as I did), that it just makes more and more sense to do things the "DIR way".