It seems there is some confusion about what randori and jiyu-waza are, and it comes out both in classes and in testing.
Jiyu-waza translates to ‘free technique’, which is a major difference of kata forms. Jiyu-waza provides a wide spectrum of possible exercises for training. The rules can be very restricted, such as always starting from a single chosen attack (i.e. cross hand wrist grab) and nage can freely choose any technique to respond with. It can also be far more open, such as uke being able to use any attack and nage can use any technique. This is about as close to randori as one can get with one major difference: if there are multiple ukes, they only attack one at a time – even though they may provide very little time between attacks.
Demonstrations with multiple attackers are almost always jiyu-wazas because despite ukes trying to look fully active, they do not attack nage from behind while he/she is performing a technique on another uke. Almost all martial art movie scenes with the hero fighting off a group is a well staged jiyu-waza.
It is fine to have rules for jiyu-waza (and even randori training, for that matter) and even to go at slower speeds for the reason of training. The more rules we get accustomed to in training, the more we leave gaps in the intangible skills of handling a full randori.
Randori translates to ‘chaos taking’ or ‘grasping freedom’ from what I was able to find, although Japanese tends to have intricate meanings to words and terms so it could mean other things. Each martial art tends to use the word randori slightly differently, which is something to consider.
Randori training can have limitations put on it for training purposes, such as not going full speed (to practice good maneuvering and positioning) or limiting attacks. These limitations are good for training certain fundamentals, but the ultimate goal of being able to perform successfully when ukes are not restricted in either speed or the attacks they use. This is randori at its highest level, at least in the aikido realm.
A common approach to randori is to have students train paired kata for several years and wait until about brown belt level to expose them to randori. This creates some poor expectations in a student, being:
1) There is no way I can understand randori until I get several years of training in technique
2) What I need to succeed at randori is to be really good at each technique I’ve been taught and I do that by more kata practice
3) I need to be really fast
I believe each of these are false and are setting a student up for failure, thus ultimately making their learning experience more difficult and frustrating. Jiyu-waza is the bridge between kata and randori, and is both fairly long and wide. As beneficial as jiyu-waza training is, there are fundamentals of randori that jiyu-waza does not cover.
Randori can be learned just like we learn any skill set: starting with fundamentals and improving them until they are executed well at speed with no limitations on uke.
The process starts with having clear definitions to what each are and a dedication to build excellence in them.