Well, if you heavily customize your site (either yourself or have someone else do it) you have to expect there to be problems whenever there is an upgrade since it's not officially supported. I think the idea that they will archive the CSS so that the vast majority of leagues won't totally break day 1 is a good compromise because what else are they to do? To make the updates that people are begging to be done requires a clean break, obviously.
Other then dynasty leagues that are still going, which is a pretty small percentage of leagues, leagues will have months of off season to adapt before it matters.
Personally I have some custom CSS based off the particular skin I'm using, but I backed off heavy customization years ago. My plan is to keep an eye on things and wait a month or two before I really dive in. But I'll pretty much trash everything I have and start out with a base new skin and then go to work off that. Even then, I'll wait until summer until I do things like bring in Habman's scoreboard because hopefully it'll be integrated in or whatever MFL comes up with will be close. Either way, obviously Habman and others will probably need to heavily modify their scripts so wait and see attitude is the best in my book. I'd rather not do more work then I need to.
That's assuming the person using the CSS knows anything (I, for one, know crap about it), or that they've logged on in the last few days to know an update is coming. That's all I'm saying. =)
Its not going to be that big a deal imo , i have 100s of site and will have to adjust them
Here is what I'm shooting for , to replace the current Live Scoring page
Its a hybrid of the Habman Scoreboard , responsive for mobiles , and also the new player popup.
Goal is for Hab and myself to work with MFL to get the new scoring / player new popup in next few months.
The nice thing about redesigning the Scoreboard and Player news popup , Habman and I are making these take the form of any existing skin , with very minimal CSS on your part. The Player news popup, may not need any additional css regardless of your site , the scoreboard needs about 10 lines of coloring done to match any site.
Your guys' work is amazing. Really exciting stuff, can't wait! The community really owes you all a debt.