I have not seen Lytham in person but if I can judge from TV pictures, the Ocean Course is not remotely as penal. Yes there is a do-or-die water shot or two (like the 17th) but compared to Lytham relatively few bunkers of the full stroke penalty type.
A lot of the sand at the Ocean Course comprises acres upon acres of lateral area which has two implications for play. One is that in many cases it is only errors of line/angle that result in the ball finding sand rather than having shots with severe distance and directional constraints in order to avoid sand. The other is that you can often playing long oblique shots out of the bunker, if not exactly toward the hole then at least generally toward the green or surrounds.
And now I'll make a serious extrapolation from my rather weak grasp of how strong players attack a very long and difficult course. My apologies if I'm totally blowing hot air...
I think properly chosen and executed lines and angle with the driver are going to generally be the strategy of choice at Kiawah. I do not think the course admits the kind of strategy that Tiger Woods stuck to throughout the Opens at Lytham and Hoylake (and St. Andrews for that matter). To lay back with 2-irons does not offer the degree of safety bonus at the Ocean Course as at a course with penal fairway pot bunkers. There's just not generally that full-shot penalty for taking an aggressive driver line that's slightly offline (except when challenging water and in many cases those will be red-staked). And there are so many plateau type green complexes at the Ocean Course that hitting 230-yard iron shots into them is a fool's errand, I just can't see enough safety with an iron off the tee to make it worth approaching some of those greens from 210, 220, 230 instead of 180 yards or less.
Anyway, in a few weeks we'll see if I'm all wet on that but I'm expecting much more interesting driver play supplemented by "working" 3-woods to play the wind and the lateral angles safely. Relatively less of the "hit it straight at the bunkers with an iron and stay short" strategy. One other difference, the Par 5's at Kiawah will be eaten alive by the PGA Championship field in the normal PGA Tour fashion rather than resisting scoring to the extent the two Par 5's being called Par 5's did at Lytham.
P.S. Let me go out on a limb with a prediction, at least a vague one. The winner of the PGA Championship will be someone who wields a surgically precise driver in the wind a la Louis Oosthuizen at The Old Course (get it, TOC and TOC?).