It comes down to how powerful static wards are, and how much technology just gets corrupted by magic. The real power of the wizards is memory and time manipulation. Close range is definitely in favor of wizards, you can't surprise them unless they are intentionally careless. They can always go back a few hours and ambush you back. Chaos would ensue if they deleted every memory before 5 of a handful of leaders.

The tech killing thing is poorly defined, but hogwarts seems to disable electronic devices within a radius. If it's similar to an emp, it may have countermeasures, but it's hard to say they also work on magic. Operating within the radius of somewhere like that would be difficult.

There's also the animagus issue. Every dog, cat, bird, or bug is a potential spy or assassin that is practically undetectable.

The big question is can spells stop a large bomb/nuke. Even if they couldn't, it would be possible for wizards to escape the blast zone pretty easily, unless they couldn't detect the attack.

I think the big weakness would be sniper fire that may be fast enough to prevent reactions at the borders of wards.