Buff the Exp Reward in Castrum.
Keep Prae a guaranteed Level and maybe abit more, like a little under a quarter.
And make Castrum give abit over 3/4ths.

The issue is compared to Prae, it feels like you dont get anything. So sure its shorter...but If the goal is to level then people will want the bigger option.
40-50 minutes of cutscene hell for a little over a whole level? YES PLEASE.
15-20 minutes for barly if even half a level? Nah pass.