It is possible to use conditional logic to hide/show sections and this can be used to achieve a multi-step form without the tabs.
We are planning on adding some new transitions to WS Form including a smooth transition between fields. We’re hoping to have those available in the next major release after 1.8.x.
With regards to hiding tabs, yes that is possible and I’m sure the remnant line and margin could be removed by adding some additional custom CSS. Perhaps we should consider adding a ‘hide tabs’ setting that does that for you 😉 Feel free to add that to our feature request page.