If an F16-Sunny day, then, at ISO100, f16 and 1/100th second. Ten stops of filter factor would put your shutter up to around 16 whole seconds, and shooting up one stop of aperture at f11 another, to about 30 whole seconds.
Sooooo, if you shot at ISO100, f11 and 1.6 seconds, with a ten-stop ND... then... the sums say, that it wasn't an f16-Sunny day, and they don't tend to come any brighter, only dimmer,.... so your ten-stop filter, probably isn't a ten-stop filter! To be using a shutter of 1/1.6 seconds, suggests that it was taking about 5 or 6 stops of light off the top.
The Nikkor 18-55 IS a tad 'soft', and the higher sensor count of the newer D3xoo's tends to show that up, but, sticking another bit of glass in front of its front element wont help any, and how much softer it would make it will depend on how wobbly the filter. A-N-D Raw-JPG conversion etc etc etc... is more techno-waffle to get lost in...
Bottom line.... AS SHOWN, fill size, on screen, no pixie-peeping.... DO YOU LIKE IT?
To me.... well, it looks like the chitty chitty bang-bang beach-arch... which is a bit of a cliche to begin with. Milky long exposure water, is more.. putting the two-together, is a bit icing the kendal-mint cake, b-u-t your photo....
To my eye, foreground beach and cliffs looks rather red, and a bit bright, the rock-arch itself rather brighter than I would expect; whole shot looks a stop or two over-exposed, pulling the arch out of the shadows..... but the sky's not blown so possibly not so far over.
Sooooo.... conception and composition..... start of the craft. Rock's not going anywhere, and you had the idea to use long exposure on a tripod, you are not rushing to capture a once only 'moment' you could pick your time of day and even year, to get the most flattering natural light and pull out detail in the rocks, both in subject arch and the closer cliffs.
At another time of day/year, you likely would have a much lower ambient light to begin with, you probably wouldn't need to use big-stoppa to stretch shutter-speed and milk your water, for the 'effect' you were after. B-U-T... potential IQ degradation using a filter could remain, the inherent softness of the Nik-Kit 18-55 would remain, and so would the nit-picking potential of the processing......
BUT.. as it stands, SILL..... DO YOU LIKE IT!??!!
At full size display, on my monitor, shrunk in pixies to screen resolution, something well under 1 Mega-Pix from the 24odd mega-pixies caught by the sensor....
Its a pleasant enough shot! The quibble over exposure is, my main gripe; that cliche, gives you a curved leading-line, taking your eye from the foreground to the arch..... the brightness and redness of that cliff then doesn't make my eye want to linger there, and when I get to the arch, I don't think that its any particular lack of sharpness, but, a bit bright, there is a lack of shadow and contrast, and the generic mid tone exposure, doesn't make me linger trying to peer into the shadows, getting any sense of mood or mystery.....
Back to fundamentals.... sharpness.... so oft argues to death, is so often NOT in the gear but the scene, and the 'perceived' sharpness a function not of the resolution of the camera, but the shadow contrast revealing 'texture' in the subject.
I suspect that the exposure, a tad high for the arch, is to a degree flattening that texture, probably more over-head mid-day-ish sun, flattening it some more..... A-N-D you are pixel-peeping....
Look at the whole.... DO YOU LIKE IT?
It's a chocolate box shot... as hintimated, its not my favourate box of chocolates, BUT, as chocolate box shot, its a fair attempt... BUT, it could be better... A-N-D this obsession with sharpness, is common, and so-oft erroneous, in this instance, I 'think' its a red-herring.
There ARE things in there that could make the shot better.... but, time of day, use of filter, metering-method, and looking at the whole scene, would make far more difference, far sooner than fretting over subtleties of technical equipment or equipment use.
Stuff the jargon..... DO YOU LIKE IT?
End of the day, that's all that matters... and if not, why not.. and if you want to do better... how; and there, I would say, start by stop pixel-peeping or fretting about popular jargon; if you want to pastiche cliche's fine, go for it, but critique the original's before you try reproduce them, and work out exactly what it is in them you want to pastiche and how they got it, and don't expect one 'trick' like an ND filter, to do it for you with a cheque-book...