Apparently Critical Strike Arcana works with Close Range Arcana-modified spells, which doesn´t work with Spell Strike. This isn´t so much a mechanical argument, but I would prefer the imagery/flavor if instead of Critical Strike granting an EXTRA, free Touch Attack (I viciously ream your guarded spots with all my force!!! And shazam!, throw in an extra Tickle, too!) it was worded to work like an Elemental Burst effect weapon with the extra Touch Spell triggering on the EXACT SAME ATTACK (excluding Close Range Arcaná-modified spells, just like Spell Strike which combines Spell Effect with Melee Attack).
That incidentally would seem to be a mechanic that makes 2 HANDED WEAPONS more useful for Maguses, because they don´t need the free hand to cast/deliver the Touch spell. So going for Bastard Sword so they can choose to 2-Hand on occasion, while still having the chance to get spell effects thru the weapon, would seem another option. /my2cents