I'm actually curious, is it the ring ropes or the mat that's harder? Because surely they could pad the latter more and loosen the ropes since there's less space between each post now.
The mat, the ring ropes aren't part of the supporting structure, and could be either harder or softer depending on how the ring is set up.
As far as padding, no. The force of a bump has to be distributed, at some point, through the ring posts and into the ground. Padding can help in more evenly distributing the weight of a bump outwards along the surface of the ring, increasing the amount of contact between the performer and the ring. (The more contact that the performer has with the ring at once, the less force is exerted back on an individual point of your body. It's the whole point of flat-backing.)
The really important measurement here isn't simply force, but force over time and maximum force. Padding, as well as the flexibility of the ring, works by taking the initial force of the bump and dissipating it over time (we're talking on the order of milliseconds here, but it matters.) You can add more padding, and it will have
an effect. To have a meaningful one, the padding would have to compress enough to absorb the weight of a falling performer and distribute that evenly through the padding surface- and on that order, we're talking laying memory-foam mattresses in the ring. Unless there's an amount of padding in the ring that can distribute that force through a large enough period of time (there isn't, without getting silly), the major factor in overall ring hardness is going to be mat area as a function of the angles of the ring (or ring posts for shorthand, until they invent the half-sided ring).
It's a harder ring, full stop.