Good to have you back Chen. I agree, basing a whole approach on a set of "dirty" techniques isn't the best idea that's not a real foundation, but it's a good idea to spend time familiarizing with them because they are something to be aware of. I believe in, as far as the physical side of self defense goes, basing your skills around a combination of boxing or kickboxing, wrestling or Judo, and BJJ or Catch (or whatever combination of those you like as long as you can handle all aspects of fighting) but applying those skill sets in unique and realistic situations. In the Army a drill used sometimes is to throw a tazer knife next to two guys rolling to build situational awareness and use of what's i nthe environment, or have one guy be slipped one to hide in a pocket to pull out unexpectedly, or to go through room clearing drills with guys who are specifically set to go into hand to hand attacks. The delivery system as JK calls it is essentially the same as in mma, but applied in different situations and with "dirty" techniques thrown in at times (in the advanced levels in the first few levels they don't do that). I had one instructor who used the sling on his rifle to choke a guy while going through a drill like this. Same fundamentals applied creatively.
Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx