Small sample? I mean if they're mostly 1st year players in NA, there's probably an adjustment period.
And at the FCL level, I'd suspect coaches are less focused on performance than fundamentals, that is, they are teaching pitches and tweaking mechanics, so early struggles are probably the norm.
I'd wait until say July and see if pitchers aren't improving before jumping to conclusions.
Given the Phillies right now have the best starting staff in baseball with exactly ONE power pitcher, I'm not worried about the lack of big arms - most of the big arms in the system have faltered.
Once a young pitcher shows they can hit 92+ on a regular basis, the focus should be on command and secondary pitches.
It's nice but very rare for a pitcher at any age to be 95+ AND have two to three secondary pitches he can command.