Huh, that Maximize Spell at 19th level is supposed to be Heighten Spell. I'll have to correct that. Can't believe I haven't noticed that before.
However, taking three metamagic feats without Sacred Geometry is intentional so that Arkalion qualifies for Spell Perfection with Paragon Surge and Quicken is a good free addition to add via Spell Perfection before further augmenting with Sacred Geometry. The table on Sacred Geomtry caps at 9th level so having spell perfection allows for an additional 4 levels of metamagic on a 5th level or lower spell.
The reason Extend was chosen is because it was only a +1 metamagic, which is on the weaker side of effects to apply for free which made it a good candidate for Spell Perfection prereq.
The reason Quicken is still a Sacred Geometry feat is because I want to apply that to all my other 5th level spells with Sacred Geometry.