One thing I should add is that with traditional rubber boots, my feet always feel squeezed when I am vertical and feet low in the water column. With an integrated sock and outer boot, I don't get that squeezed feeling.
Laces on the "inside" side of the boot would be fine and would be easy to reach when gearing up or getting out of the boots and would be reasonably snag free. A pull cord with some sort of slide lock would be fine as well.
But, there is also nothing wrong with laces in the front. Something you might experiment with is a lace up boot (standard front or side laced) with a zipper in the middle of the laces (something like what used to show up as a lace option on combat boots back in the day). You'd need a decent plastic zipper like those used on wet suit boot, but it would allow both adjustability and ease of entry. The major advantage of a lace up boot is that the fit and width of the boot can be tailored to fit your foot and different sock thicknesses. Traditional rubber DS boots feel sloppy, and that adds to the squeeze issue as well.
In either case, if you use laces, you need a place to put the excess cord. One thing I like on the EVO 3 boot is that I can lace them up and tie the knot toward the inside eyelet of the boot, and then tuck the excess cord under the tab that wraps around the boot and supports the last pair of eyelets. It keeps it very clean with nothing sticking out to create an entanglement hazard.
I'm a definite fan of a heel and at least some arch support as it greatly aids walking as does a reasonably aggressive tread - but don't go crazy with heel, arch or tread as you want it all to fit in an XL or XXL sized fin, and the primary role of the boot is swimming, so it needs to retain good feel in the fin.
Material selection is also important. One of my major beefs with the DUI rock boots is that they just don't hold up well and basically start to rot and fall apart. The other major objections are the flat sole and generally poor/floppy fit.