In general, yes, Future World is most crowded from park open to late afternoon and the crowd at World Showcase builds as the day goes. But it doesn't mean you can't do WS in the morning. We do it all the time. In WS, the 2 big rides that are tough to get are Soarin and Test Track. Soarin has gotten a lot better since they opened the 3rd theater, but it still gets crowded. TT is still the same, it gets busy quickly and is weather dependent, so that's the one I'd try to get on first. What we've done, more than once, is get to TT either right at park open, or very shortly thereafter. Then get off that ride and go right to Soarin' for standby. If you do that, you shouldn't have to wait more than 15-20 minutes for Soarin'. Joy and Sadness meet and greet doesn't have FP+ and that line can get long, so be ready for that. Otherwise, the rest of the rides in WS are relatively easy to ride standby or via FP+.
Now...FEA...that's a whole 'nuther ball 'o wax. If you can snag a FP+ for it, do it, they go very, very quickly. If you can't snag one, our experience is that if you get there by 10am, you won't have to wait super long in standby line. If you're there after 10am without FP+, good luck.