Your statements are contradictory. You say it feels like a real Pacman stick... then you say your not sure what a grommet would add. Meaning... you either cant remember what a real pacman stick feels like, or you have only ever used a generic Reunion stick... or similar Inferior replacement.
I think very few folks here actually know what a factory-fresh Pac-Man stick feels like (perhaps not even you.) Usually, by the time anyone used them on a machine, the grommets were well broken in, if not quite damaged. Personally, I like the feel of a good grommet stick over the spring centering, but they are not without their own idiosyncrasies. Most don't know this, but those "centering grommets" were not designed by the arcade manufacturers to do the job they ultimately ended up doing. They were an existing item, used in a very different industry, and re-purposed for the task. As such, they suffered a lot of wear, and basically started being damaged almost immediately, being that they were subjected to forces well beyond what their design anticipated. That's why when you buy a used grommet stick, the grommet is usually destroyed. They are quite stiff when new.
They are durable. But they are ugly, and have a ton of friction to them. Their typical leaf-micros often get bent and warped, making diagonals a wench to activate.
After someone beats the heck out of them in a commercial environment, and the restriction becomes worn, then it's possible for the actuator to reach farther than when new. I haven't seen this ability to push the actuation far enough to bend switch levers on a new stick, but it's possible if the levers have been bent inward. If anything, diagonals on a Super might be too sensitive for some, especially after using a Competition. Regardless, your assertion that the Reunion "is a Super" is just incorrect. Completely different shaft, actuator and restriction pattern.
The REAL Pacman sticks, use a center pivot grommet. Unlike a spring pivot, which creates a stick-offset as well as a good deal of resistance to get it going... A grommet will allow the pivot to remain in perfect center, for faster activation due to less distances traveled. It also has a uniform resistance, which is pretty light. Where as a spring based has a range of resistance that multiplies until its surpassed. That initial surge, or WALL of resistance, is felt every time you have to roll past center.
Again, not entirely correct. Rubber grommets absolutely do not have a "uniform resistance". Resistance with a rubber grommet starts out small, and increases very rapidly the farther off center it is pushed. 4-way joysticks typically have a fairly long throw, so that higher resistance will be reached pretty quickly in use. It's also important to note that the farther off center the grommetted shaft is pushed, the more twisting of the grommet center occurs, thereby increasing the damaging effects of using them in this manner. This is why they are torn up so badly on older machines in disrepair. On the other hand, the spring centering is much more uniform in resistance, with the exception of the small bump at the center. My own tests show that a Super, extended to the restriction limit, requires about .75lbs of force. A grommet centered stick, with the same shaft length, takes about .97lbs of force to move the actuation the same distance. So yes, it's true that grommet sticks are smoother across center, but that comes at a price of longevity and more resistance. It's also worth noting that a Competition, like other spring centered sticks, has the same positive centering, so it's nice to see that it doesn't bother you on that model.
Bear in mind that in this particular assembly (one I know you have not tried before "poo-pooing" it) there is further reduction of forces required for actuation, due to the fact that the 100gram activation force switches have been replaced with real leaf switches, which not only reduce activation forces by ~90grams, but also have a near zero distance "reset" before being activated again.
In other words, a little experience and data from the actual item can go a long way when making an assessment.