I think 15-25% will make no one use it, or very few people. It's true there are protocols that charge nearly or even upwards of 50% penalty for a maximum stake early withdraw, but those protocols may also have 1-2 year staking periods.
For now, I am happy increasing the proposed fee to 5% and see how that goes
I think it's 4% or 5% per week. So, Let's say I unstake 100k SPS (25k per week), if I quick unstake on week 1, that's 4% * 4 [weeks] = 16% = 16000 SPS penalty
I may be wrong but that was my understanding.
If it was 5% all throughout, then I do agree that it is too low and the minimum should be around at least 10% for the whole 4 weeks. Then put 5% burned and 5% transferred to DAO for other projects.