I don’t think it’s sluggish, I think it’s as Henrik is saying it’s just more responsive.
It’s hard to define to be honest since we can only judge it on how it “feels”.
For me it “judders” more I think, so the old system didn’t poll as often so had to smooth things out, now there’s no smoothing. But the difference it noticeable because although it may be polling more often it still doesn’t seem to be enough to match the fluid feeling it had before.
After trying it for a bit you can get used, to be honest it does feel more responsive which is obviously a plus, but it just doesn’t “feel” quite as good as it did. Perhaps some level of smoothing could be reintroduced, say via optional checkbox? I mean presumably the code to do that might actually already exist since it was used under the old vjoy system? So maybe that could be repurposed but with say a smaller buffer so it doesn;t dumb it down too much.
Again it’s hard to talk about because it’s all on how it feels but it seems like the sliders are out of whack a bit now. Since the sensitivity has been amped up you’re likely to have the sensitivity set to a different position than you had it before and because the three sliders actually all affect each other this sensitivity change feels like the deadzone/gradient slider’s upper/lower ranges may need recalibrating at Tobii’s end.
Again hard to be sure but it feels like once you get deadzone to the correct place, even one notch up/down shifts the deadzone massively meaning the range doesn;t seem right.