Realistic training means sometimes going outside of your comfort zone , a lot of people aren't willing to do that for whatever reason.
If you are doing the art primarily for self defence then you must be brutally honest with yourself and want to continually improve your speed , force and reflexes.
That means sometimes putting the head gear on and enduring the discomfort that comes from being hit in the head , it means a lot of sweat and sometimes blood.
But it is being able to endure that discomfort and still keep going , that is what forges your mental toughness , a quality that is needed in self defence situations.
. . . . Along with the forms a good sized chunk of your training must be engaging in hard chi sau sparring with moderate to heavy contact to the body .
Drilling of your reflexes by training against all types of random attacks not just Wing Chun style attacks.
This must include grabs , punches from all angles , kicks from all angles , tackles , multiple opponents , basic groundfighting and unarmed against weapons.
Your deflections must sometimes be done against full force attacks in order to test their integrity so that any mistake can be worked on before you have to use it on the street.
. . . . Which could be the case if all you are used to is doing gentle chi sau and you haven't worked on your reflexes from out of contact range.
You must also do a fair bit of power training on various pieces of equipment such as kick shields , focus mitts, wall bag , heavy bag etc.
I think as long as you work on speed , force and reflex in your training as well as using a bit of common sense then you can become a decent fighter.