Monster upgrades! (Part 1: Ocularon)

[Nytemare3701]

First up the Ocularon from Fiend Folio, a Large aberration with:

(click to show/hide)

90(!) Perfect fly
Perfect vision (true seeing, blindsight, and immunity to flanking)
DR 10
Acid Immunity
Regeneration 4
A host of annoying spells (Passwall, Darkness, Invisibility, and At-Will Arcane Eye)
A STR/CON poison with a decent difficulty (DC19) that it can use from the next room over due to it's weird attack methods (floating eyeballs that explode with poison gas)

And finally, 4 tentacle attacks with improved grab, which force a DC20 Fortitude save or PERMANENTLY BLIND the target as it forcibly tears the target's eyes out to use as explosives.

All wrapped up in a CR 12 package. It has 5 feats and 19 INT, so it's not going to fight stupid either. What can we replace those 5 feats with to make it stronger?

The poison and eye stealing abilities are (Ex) and force saves. Is there a feat to bump those?
Freedom of Movement is a pain to deal with for grapple monsters. Would having Dispel on the tentacle attacks help with that?

[Ithamar]

Ability Focus helps with the save DC, and I think there are a couple feats in Serpent Kingdoms that will make the poison more interesting as well.

[awaken_D_M_golem]

Flyby

slightly imbalance the stat load out, to up the saves #s
(technically the dm decides if some magic tripwire gets sprung)


Definitely wants to hit-and-run until most of the party is blinded, so like TrueStrike-ish stuff.
Can take hits, but wants as few condition tags as possible.

Guards/Wears any +saves item treasure, in a party's semi-wishlist.

[PlzBreakMyCampaign]

I agree with Ith, always pump any DC you can't force 20/(Number Party Members) per turn times.