Hi, this poke is fine and will remain as it is now, we already checked it and is totally fine.
As you've shown, other pokes have stronger Volt Switch than Magnezone, the reason is that Magnezone has the lowest cd on this move among these pokes, only Shiny Lanturn has same cd and is stronger (Obviously because is a Shiny version), Luxray has 25s cd so it deserves to be stronger, Emolga has 20s cd so it also deserves to be stronger too. Still, it has 100 dmg x1 under average, the reason is simply for balance.
Bolt Strike is a weak body vs body move, 1600 dmg x1 is 100 dmg over average for this kind of move, as Raissa said above, pokes must have weak moves aswell as medium and strong damage dealing moves.
About Electro Spin, idk if you even checked the formula, but that kind of formula has average 1.1k dmg x1, 2.2k x2 and it is 100 dmg x1 OVER average. (You can confirm seeing Whirlpool, Heat Wave~~)
As you can see on this image, it has 3 weakness, 1 single type making damage x1 to it (Keep in mind that Ghost and Dark type are making x.5 to Steel, we haven't reached the generation where it changes to x1), 13 TYPES MAKING DAMAGE X.5 OR LESS TO MAGNEZONE (Ghost, Dark, Normal, Flying, Rock, Bug, Steel, Grass, Electric, Psychic, Ice, Dragon + Future Fairy) AND A TOTAL IMMUNITY: Poison.
Metal Sound damage is the common amount for that kind of formula too, so in conclusion, there is nothing to change about it.
It has 2 weak moves: Thunder Shock (Distance move) and Bolt Strike (Body vs body move).
It has 5 moves with medium damage: Volt Switch, Electroweb (Also Paralyzes), Magnet Bomb, Charge Beam, Electro Spin.
It has 2 Strong damage dealing moves + 1 without damage giving stun: Electric Terrain, Metal Sound, Super Sonic.
As an extra, learns Doom Desire, Tri Attack, Discharge and Reflect as strong TMs (As you'd like to choose)
TM Learnset:
TM15 Hyper Beam - level 30 - 30s
TM17 Doom Desire - level 60 - 50s
TM32 Tri Attack - level 30 - 35s
TM33 Reflect - level 50 - 60s
TM39 Discharge - level 60 - 50s
TM66 Parabolic Charge - level 30 - 20s
TM82 Nuzzle - level 40 - 25s