All I can do is tell you what we have experienced since FP+ started on our trips. We go at times with the same crowd levels. Not high crowd times- generally the crowd calendars are in the 4 to 7 range. The park does not feel any more crowded. The paths are about the same, lines for food the same, no big lines for bathrooms- all just like pre FP+. We are used to having lines of 10 minutes for Small World and POTC even in mid-afternoon. We are used to walking on to Nemo and Figment or having no more than a 5 minute line.
We experienced lines at POTC and Small World at a minimum of 30 minutes in the afternoon. POTC was often 40 to 45 minutes in the afternoon. We have NEVER seen that before except for the year we went to WDW between Christmas and New Years.
Nemo was 20 to 25 minutes by 10 or 10:30 in the morning. Figment was half an hour in the afternoons. I have not seen Figment have over a 10 minute wait at the times we have been to WDW in 10 years.
Because of the tiers, we observed the single rider line at RNRC at 30 minutes to an hour, usually in the 40 to 45 minute range. We are used to it being 10 to 20 minutes tops. Usually when we get to EPCOT at rope drop (not at the front of the pack), we can get to Soarin with it having a 15 to 20 minute wait. Now, it is already 40 minutes by the time we get to it.