drop bear
Sr. Grandmaster
There are nuances. The biggest blurring I have is between Kali and WC since my current teacher teaches both in a manner where the transition from standing WC to using Kali to avoid going to ground is pretty seemless. The main point was though, once on the ground, Wing Chun is lost because it has nothing.
In terms of unarmed and armed TWC and the Kali I study are very close so the swap to unarmed vs weapon doesn't take a lot. It's more a mind set change. WC tends to be singularly "tight" in its thought and movement. Kali "widens" out a bit naturally because of a different mindset. WC has weapons but the main focus is on the open hand. Kali is actually an MMA in and of itself but it assumes people are armed or can quickly arm themselves and thus it widens but that is more of a mental switch than a technique based one.
Studying those two arts side by side actually made me notice something. Physically they are very similar however the mindset changes. So if unarmed I think "check" near the elbow is a punch is coming in. If the other guy is armed my body uses the exact same "check" but my brain/instinct tells me to do it closer to the wrist with wider footwork because of the knife. So sometimes the same movement, with a different trained mindset mindset making a small alteration is all it takes.
I treat them all as a lock I am trying to pick. If I get the right sequences I dismantle the other guys defences. And the other guy will have a bad day. Mindset for me doesnt change.
It is just learning the basic rules of the situation.