If you re-render, do so into DV. You cannot magically gain what isn't there. It's like expecting a worn, pre-electric, 78 shellac record of Dame Nellie Melba or Caruso to sound like a DDD CD! (OK, perhaps I exaggerate!)
You don't say what system you are using. NTSC DV is worse for colour artifacts than PAL DV. In both cases, there is one set of colour sampling for 4 pixels, but the way it is done is very different. If you want to delve into it deeper, NTSC has a 4:1:1 colour space, meaning that on each line the colour is shared between 4 pixels. In PAL, it is 4:2:0, meaning that the colour is shared between 2 pixels on every other line, but, because it is interlaced and the colour "burst" is phase alternated between lines, it gives the appearance of a much better colour resolution. When a DV signal is taken into any app (or a TV), the 4:1:1 or 4:2:0 is converted, as best it can, into 4:4:4, i.e. every pixel has full luminance and chrominance. When this signal is re-rendered (not using Smart Render), the codec you use will do its best to restore it exactly as it was, but small variations, normally invisible for ordinary TV viewing, could occur in chrominance encoding, usually poorer for NTSC (hence Never Twice the Same Colour!
). This could also be a function of the codec you use; some are created more equal than others. Normally, the only time you would normally be bothered with NTSC colour space is when keying a blue screen or green screen, where you might see some horizontal overlap fringeing.
Anyway, because uncompressed shares the same chrominance signal over each block of 4 pixels, you gain nothing by repeating it 4 times, rather than recording it just once, and you lose a lot of disc space plus the risk of the larger required bandwidth causing video glitching if your HDD has difficulty in coping with the bitrate.
Sorry, I can't compare with VS7 as I've never used it.
Hope this helps.