Revolution Slider guys have just released a new update so please make sure you update to that version, however regarding the customization being removed, slider update should not cause any issues with theme customization at all since both have their files at different places.
Every one of my loops on ever slide no longer work. I have been working for hours trying to find the issue, than fix it. If I do not find a solution soon. I am going to revert back to the previous version.
We have re written our functions after 12 hours of work, i think that we are moving away from revSlider now after this. I know that updates are always welcome but this is a massive change in one swoop that just does not work for us with some of our sites. We needed an excuse to move back to simpler functionality away from sliders anyway.