Trend in ionisation potential in period 2
Emperically speaking, Be is on the "metallic" side of the table. Lower IE than non-metals is obviously expected. 

A quick glance at the $IE_1$ trends for period II tells us that like the OP noted, Be certainly has an abnormally high $IE_1$, deviating significantly from the expected plot, due to the fully filled configuration.

However, Carbon (Z=6) has a higher nuclear charge(=more protons) than Be (Z=4), a smaller radius and hence a stronger hold on its valence electrons. 

Even Nitrogen displays an exception, due to half-filled $2p$ subshell, as evident in the plot.

Just because of a tiny bump in the plot, expecting N and Be to have higher IE than all the elements of the periodic table is clearly an exaggeration.