Can you show an example of where you believe them to be hard to see?

At many sites, the symbols for unusual activities can be difficult to see and may be overprinted by the site symbol.

as you have deleted the circles, could you make the activities symbols more evident?

We removed the radius circles because some countries do not publish them at all, and parachutists are often to be found outside the circles anyway. People were planning their flights to just skirt the "edge" of the dropzone, and then forgetting about the zone and thinking they were safe. It turns out there is really no edge at all, so for us to show it is actually unhelpful. We will still warn in flight (and while planning, if that option is turned on) if your flight goes inside the "edge" but we deliberately do not show it normally.

Is it me, or did SD (at least on my iPad) used to show the limits of parachute DZ's with a circle similar to (but not the same as) a ATZ - and now doesn't?

Same applies to glider sites - there's just a glider symbol shown on the chart with no depiction of the limits of the "launch zone" - and I thought there was.

I get rather nervous about these "sporting areas" & obviously want to avoid for safety reasons, especially as radio contact can be "intermittent" - but at the same time I want to ensure my routes are as efficient as possible. & not give an unnecessarily wide berth.