there is one synergy that pyro have with runecaster. enchant fire with rune of giants. the giant jump acts like an autoattack with UNLIMITED aoe ratio (for wiz uses matk, others physical), and passes cafrisun/etc. effects. pyro1 rune is not that great though, since enchant fire scrolls replace this.
unfortunately… rune of giants skills are limited to wizard base class and other runes. wiz3 synergy with pyro is terrible (agny bonus is additive). if unlocked in the future, links would be quite potent with this… the true melee wizard.
rune of destruction seems to function similar to magic missile- shooting one bolt off each target randomly. given how links were changed to limit the MM link combo, this has also affected rune of destruction and it currently doesn’t stand out among aoe skills with linker.
a build that hopes for the future of giants being unlocked would be pyro link3 rune FF2. put down fireballs near the boss, link, and stab the fireballs. note that this build will not be that effective in TBL, as it is rare to get quickcast through spiritual link.