Don't Worry. You'll have a great time and the fact that you are planning and researching will put you ahead of 90% of the wondering masses at WDW.
While it's been a number of years since our families last visit, we have usually planned using a combination of Touring Plans and EasyWDW. That has always worked for us and as a point of reference we spent 10 days in WDW with another family a few years back. The first 4 days, we used the "Hybrid" plan. The next 2 days, the other family decided to "wing it" because they felt the plan was holding them back. We ate together every night and discovered our family (with a plan) accomplished WAAAYYY more each day and most importantly our waits at the rides we each experienced were far shorter. The last 4 days, they were back on the plan and on our heels every step of the way.
When I received the email update on the crowd calendar, I too was nervous. Our family is visiting WDW over Christmas...needless to say, planning is a must. After re-looking at our personal plans from Touring Plans (which is what we had to base our fast pass selection on), it appears that very little time in the parks have changed. While the order of a couple of activities changed, the highest increase was 6 minutes and several decreased a couple of minutes. On December 20th, Touring Plans actually suggested a different FP and I was lucky enough to get it. That actually lowered our time by 32 minutes. YEAH!!! I do believe the statement it is more important to have a good plan for the park instead of having no plan for a park chosen based on the crowd calendar.
Lastly, I know there has been a lot of discussion as to Touring Plans missing the mark on crowd numbers recently and the fact that EasyWDW is looking more accurate. I wouldn't begin to guess at how complicated these forecast must be, but I will say I appreciate the fact that I have something to use. I have always enjoyed Josh's site and continue to use it, but as of today, there is still no recommendations published on the site for December 20th thru December 31 (less than six weeks out); far beyond the date for ADR's and even FP+. I realize that Disney is still in a state of flux on the opening hours but if you are going to plan (which most who visit this site are doing), I would prefer to have a suggestion that might be off by 10 minutes than no information at all to plan by.
That said...Keep a positive attitude and you'll have a great time...its the Happiest Place on Earth after all....