imo the modular ports are a massive longevity feature. charging cable ports are one of the most common laptop killers, so making that modular is a huge step up
Larger port module plates that bolt into the sides of the chassis with a few screws would be just as good from a longevity standpoint, would enable better rigidity, and would allow the FW13 to host a considerably higher number of ports.
A screw or two definitely wouldn't have impeded the handful of times I've moved my 16's parts around, not even in the slightest, it's just not that frequent. And I don't usually carry other kinds of ports + wouldn't be able to have the screwdriver too, it's usually "I have them all" or "I have none" and then all I can realistically do is swap sides. I'd have zero complaints with some standard screws.
... but tool-less lowers the barrier to literally zero, which is pretty big when you need it. It's a very different mental-space: absolutely zero concern.
... and if they were smaller, they'd be incompatible, and it'd be harder to build custom ones due to even less internal space.
i bought maybe 5 differnet thinkpads over the years and never had an issue with the old charging port. with the last usb-c thinkpad i got i had to buy 2 new chargers and both of those i repaired a few times as well. the connector just wiggles around too much and the cables are also too rigid so when it gets snagged on something the connector ends up bending in the port before the cable bends.
in the end i just got rid of it before the actual port on the motherboard got completely damaged