Aegis and ochain are already perfectly reasonable at their current powerlevel compared to the work they take to farm.

You can achieve 100% interruption rate down without gimping yourself while casting.

The loss of a few hundred HP from swapping off HP+ gear is just a necessary evil of wanting to achieve max interrupt rate down.

You will lose a total of 270 HP doing these swaps, and by swapping other pieces of gear correctly though you can maintain that 270 HP still and still have the 50 PDT/MDT etc etc.

I would like to see something more worthwhile added to 99+ Ochain, since it takes about twice as much effort as a 99 aegis. Preferably I'd like to see a Shield Mastery bonus added onto Ochain at lv 99.