Cautiously optimistic for them. Sigma faces some steep competition against Canon/Sony/Nikon but might be able to find a niche like Fuji has with price on one hand and lens+color fans on the other.
No IBIS is rough, because its definitely a useful thing - the R6 III has 8.5 stops for $2.7k, same price as the FP2 with an EVF. At $2.2k, the partial stacked sensor might reduce the jello effect, might not. It's an interesting tradeoff and it'll come down to whether the AF is good enough to make the 20 fps it shoots at usable. For example, if you shoot 30 fps but the AF doesn't work, 28/30 shots being blurry is a waste. The flagship cameras can get 60-90% keep rates if you do your part, so I'm curious what Sigma's system can pull off outside of a studio.
I think the biggest problem with a minimalist ILC is that a commodity body stops making sense bc once you throw in even a few decent lenses and the usual other spend on memory and lights, you're outside of the budget range. You don't _have_ to have Art lenses and nice gear - one of my favorite fun lenses is a $150 lensbaby experiment, but the gap between a decently rounded Canon kit and a Sigma kit closes in price and widens in capability fast once you get started, at least gear-wise.