Not likely going to happen.
Everyone is held accountable under the same ETF agreement, terminating earliy is going to cost you $175.00. Unless you only have 3 months left on your plan then you can expect to pay the full ETF upon your termination notice.
Folks who have reduced or waived ETF's have a history with VZW tech support that well documents the limitations. When VZW gets tired of replacing the device under waranty they tend to be more open to reducing or waiving the termination fees. Your best bet here is to keep calling into VZW and working with Tech support. Ask them to look at your history and see what options they can come up with for you under replacement or early term.
From what you have described here you do not have anything that is out of the ordinary for these devices. MiFi's were never intended to be left online for long peroids of time. Treating them like an always on internet connection is bound to cause momentary disconnections and gaps in service.