Personally, I believe 5% is a rather large deterrent already and would personally not use this feature unless something drastic is happening in the market.
The point of this proposal is to enhance the flexibility of stakers while providing us an additional source of SPS burn.
With that being said, it does definitely seem like the majority of the people commenting prefer a larger penalty. Even if this proposal passes, I would not be against a follow up proposal to increase the fee
5% is a market fee. It's literally what splinterlands charges people selling their cards on the site. And it's not a deterrent. If this fee isn't a deterrent (which I'd argue 5% isn't, and splinterlands' own website shows they don't either), then the 4 week unstake period effectively ceases to exist. It only works if the fee is somewhat punitive.