It's possible, but I don't know whether it would be feasible. We have yet to know how they powered their machines (LeyLine Reactors? Windtraps? Purified Jewel Seeds?) and I can't help but giggle at the thought of mages raiding nuclear reactors across earth for DU.
And for area denial weapons won't chemical or biological weapons work better?
BTW, it still bugs me that in Force the protagonists skipped right to making AEC equipments (on-screen). No-one ever thought of making spells that instead of manipulating the entire attack, merely converted magic energy into mass-based attacks so that not even their anti-magic could fully disrupt the shot? At the very least, how Stardust Fall works shows us that Nanohaverse mages
can use magic the Jedi way aka lobbing object towards the enemy; why not make railgun-like spells? Real Laser attacks instead of pseudo-magic one?
Even if for some reason they're not as good as the AEC's, it would still make a decent stopgap countermeasure while waiting for the new weapons to be produced...