If you intend to fly a paramotor, inspection and maintenance will be one of the things you should learn and must do. Your thoughts about the mounts have probably been the same for many new pilots over the years but the reality is they don't often fail and in eleven years I've not known any sag (although I generally get a new machine every three years or so). If you look at machines like the Parajet Maverick you'll see that there is also webbing on the mounts. But replace them with manufacturer approved mounts every year if it bothers you, it's an easy job on most machines. Certainly cheaper and less hassle than making your own.
As for the netting, if you don't start you machine on the ground (which you absolutely mustn't) then it's unlikely you'll need to worry about your hand holding a throttle going throught the netting.
Give yourself some time in the sport before getting too het up about how flawed things appear. Nothing's perfect and the machines are constantly evolving and improving. If you can add something that will make the sport better that's great but we have been here with a lot of things many times before.