Ignoring the active, Ohmwrecker is a solid item.
Ignoring the active, just look at what it offers.
For only 2650,
has:
300 hp
50 armor
150% base HP regen
10% CDR
+Point Runner
In comparison,
for 2900 has:
425 hp
60 armor
+Dreadnought/Crushing Blow
is 95% gold efficient, 125% when near towers.
is only 80% gold efficient, 105% when you stack up the passive.
Even if you aren't using the active very much, Ohmwrecker is pretty good.
Is Ohm some kind of hidden OP? No. It's not godly, I'm just saying it isn't shit and it should be considered when the situation calls for it.
Are you losing lane to an AD as a tank? Pick one up. Do you need an armor/HP item and some CDR? This is an option. Are you a tank support who already has Knights Vow? Go ahead?
While I'm on the subject, pinging your Ohmwrecker makes you say that it has "0 charges". C'mon, Riot.