You’re really only losing out on Energy Blast and 1 Inch Punch, which isn’t too bad if you consider what other skills are available by rank 7, like Goddess Ausrine statue(18sec immunity) if you went diev route and Status immunity if you go PD, which is arguably far more valuable than more damage in PvP.
You know the name of the gem that gives more skill level?
True, I was thinking about DievC3 in fact, anyway lets see what new ranks come
You can see there lots of monster gems for every skill