First let me say I am not an FA, nor do I enjoy typical WG art. Also, I am not a typical BI fan, and do not enjoy typical BI art.
What I envision is a middle ground between the two, combining my favorite aspects of each.
Body Inflation: I love the taughtness, the rate at which the expansion happens, and the 'tight and bloated' look. The lines are tight, not dimply or jiggly.
Weight Gain: I love substance. The person isn't simply expanding, they are feeling 'heavier' and 'gorged'. They have an ever encumbering mass they cannot control.
Arcanumbot's Conceptualization: The 'victim' as some people call them, are overcome with a sudden full and heavy feeling. It's not gas or a liquid, but the victim is actually getting fatter.
Unlike regular weight gain, the rate at which the victim is fattening gives their body a tight, bloated, body expansion look.
As for texture, they are not soft and squishy like FA art, and they are not 100% taught like BI art. They are being stuffed full, and thus have a 'stress ball' type texture. It is soft to touch, but gives resistance quickly.
Many times the 'victim' becomes so bloated with fat, they are unable to do little more than wiggle their limbs as they struggle to waddle around.
Of course there are always two outcomes:
1. The victim is left forever a bloatd parody of their former selves
2. The victim gets so incredibly fat and bloated they instantly burst into a billion pieces.
I'd noticed that kind of 'middle-ground'ness in your art. It appeals to me as a BI fan, and I'm sure also to WG fans and FAs.