Way too many people use ankle weights as a crutch to keep their feet down out of fear of having a feet first ascent. They don't realize how important proper weighting is to proper and effective use of the drysuit. We teach our students from the start not to use ankle weights and to manage the air in their suit to get good trim. I need a bit of air in my boots to keep my feet up and my body horizonatal. If I end up looking down on something and my feet go up, when I am done looking, a quick tweek gets the air out of my feet and my trim back to horizontal. That does not mean we do not have ankle weights handy for those students who do need them. Not everyone is built the same and sometimes body composition dictates a bit of weight needed on the ankles. There is a time and place for everything. We just wait until they are actually needed before we use them.
We dive frequently with divers who have lots n lots of dives and still use ankle weights. When we stop to look at something, all of them drop their legs and end up kneeling on the bottom disturbing the sand (or herring spawn, yuk) while we hover off the bottom. That is they way they were taught, have always dove, and are therefore comfortable with. Each to his own.
I think there is definitely a difference in the need for ankle weights between diving a suit with built in boots vs a suit with socks and rock boots. I have been in both and can see where those who are not great at managing the air in their boots might feel more of a need to put on a bit of weight on the ankles. I like a bit of air in my boots as it helps keep my body horizontal, but then I am quite comfortable moving my body slightly as needed to reposition the air.
One thing that really helped me with my trim is switching from a weight belt to a weight harness. I use the DUI harness and have it positioned down on my hips rather than up around my waist. When I changed my fins from heavy jet fins to light Manataray fins, I adjusted the harness down a bit to compensate for the weight and am able to keep my trim good.
Just my 2cents worth.