About early swap termination:
Usually if you pay back a credit earlier than it expired you have to pay an extra fee.
This could be used for swaps too. It doesn't need to be high, just enough to discourage swap-hopping if a slightly more attractive swap appears than the one you're currently borrowing.


About FRR:
I think the "delta" stuff would make everything more complicated for lenders, but effectively change nothing about the "wall" effect of FRR and it's manipulative effect on the market. In short: It's pointless and only adds annoyance.

I like two other approaches:
Maybe make FRR only available for the shortest possible lending period, which would be 2 days. So if the wall of "easy route" lenders appears at FRR, it will still allow "real" (custom) rates for all those who need more reliable swap periods. However, I don't like this somewhat arbitrary approach that affects the short-period part of the market negatively. Instead:

I like the suggestion that has been made to change the adjustment speed of the FRR.
A couple days ago when BTC started to rise the FRR was repeatedly the lowest rate by far in the list. This should NEVER happen, it shows that the FRR adjusts not well enough. In general, since the FRR is the "most convenient" feature, it should always appear at a "premium" to make it less attractive and not drive rates down.
So, as someone suggested, FRR should adjust upwards quickly and downwards slowly, and if you make it an average of market offers, it should not be in the middle but in the upper third! Because this way it gives breathing room for a true market to form below it.

Thanks for reading^^