More original content (I warned you it was coming).
Much has been written and argued about the "ultimate" or "complete" martial art. In my opinion, there is no "ultimate" or "complete" martial art - all offer something useful (more on this in a second).
To argue between Hung Gar being more "complete" than Wing Chun (or Savate, or Tae Kwon Do, or whatever) is a waste of time. Any art that acknowledges and uses the four limbs of the body (two arms, two legs) and covers the range from striking to standup grappling to groundwork will have the same ultimate end. They must also recognize that the mind (and will) are extremely important to the fighter.
Where I think the problems arise are in the training methods that have been passed down to the martial artist through the years. Sensitivity training (Chi Sau, push hands, etc.) are ways of training the fighter to be aware of body position, energy flows, balance, etc. But it is not the sole province of Wing Chun and Tai Chi Chuan players - wrestlers and jiu-jitsuka also train in these areas - the rolling on the mat with a resisting partner are teaching the grapplers the same skills, just on a different plane (or level).
As an example, if your art is primarily thought of as a striking art (like YKM) - research the movements from the form and start to apply them in a clinch position, on the ground, etc. The core movements (spiraling actions, circular motions) will be there - but train it as you trained the stand up portion - slow and easy with a partner who is also there to learn, not compete. Later after the movements become better known/ingrained, start to encounter resistance, leading to full contact work.
Even the MMA folks start this way; they don't just jump in and choke each other out - not much training going on if they did, only people already trained would be any good. Good partners can help you "discover learn" great things about you and your art.
If your art puts sole emphasis on one training method, you may start to feel the lack of attributes being developed. It may be you have become locked into only one aspect of the art.
Look at the training methods of the various arts (bag work, throwing, conditioning) and adapt them to your art, looking for fluidity and flow.
Remember, we are tool using primates - use them to train smartly.
As tool users, your art should also cover weapons and multiple attacker options - if they currently do not, research the training methods of those arts that do, adapt them to your methods and see what develops.
I did some single stick sparring with a friend, and he commented that I fought like I had a Chinese broadsword in my hand - I was applying what I knew (Chinese MA) to Filipino MA - using my "style" in a foreign training "method". All I know, is it seems to work for me, opening my eyes to gaps in my training, not necessarily my knowledge.
If it is confusing, drop me a line and I'll explain better.