I just think with Penning we have to let his development play out. When drafted it was clear he was under-developed technically, but with the right tools, etc. It was always going to take time. At this point he managed to start a full year and he has a number of things to improve on, but the platform he is on to improve is much higher than it was in the off-season.
And in general, OL tend to need that 2-3 years development to become what they will be. Saldiveri is another case in point - he has underwhelmed so far but he can still turn out good. There are plenty of exceptions but letting these guys grow into starting roles often is what is required.