The seat of Montgomeryshire is set to disappear in its present form.
North Shropshire escapes unscathed from the proposals.
Elsewhere, Ludlow and Leominster are combined under a new parliamentary constituency, Bridgnorth will merge with Wellington and The Wrekin, and the existing Telford and Shrewsbury constituencies will be enlarged slightly.
But the biggest shock comes in Montgomeryshire, which will be split in two, with the northern half of the constituency, including Welshpool, being merged with Clwyd South to form a new South Clwyd and North Montgomeryshire constituency.
The south of the constituency, including Newtown, will become part of the Brecon and Radnor seat, which will be renamed Brecon, Radnor and Montgomery.
Mr Davies said: "I believe parliamentary democracy in Mid Wales will be hugely demeaned if these proposals go ahead, a lot of people won't know who their MPs are and there won't really be a parliamentary democracy. It leaves me feeling incredibly sad and disappointed."
The North Shropshire constituency, held by Owen Paterson, is the only seat in the constituency which will be unchanged.
The draft proposals will now go out for public consultation. Final plans will then go forward for ratification in October 2018.
Under the plans, the Ludlow seat, which has been held by Conservative Philip Dunne since 2010, will merge with the northern part of the North Herefordshire constituency, held by fellow Tory Bill Wiggin, to create a new Ludlow & Leominster seat.
The existing Telford constituency will be extended to include Donnington, Hadley and Leegomery, which at the moment come under the Wrekin constituency. The proposed Bridgnorth, Wellington and The Wrekin constituency will also take in Much Wenlock and Broseley, which are at the moment part of the existing Ludlow seat.
The village of Atcham will disappear from the Westminster map, with the Shrewsbury & Atcham constituency renamed as just plain Shrewsbury. The constituency will be enlarged slightly to take in the wards of Chirbury and Worthen, which at the moment fall under Ludlow.