I think a donation fee is ok. Its fair to give developer a share, and this way everyone donates proportional to their "income".
5% is not okay though because we have electricity to pay for too ...
Why not?!
A miner which gives you 2x the speed of regular one (if any!) and you think 5% is too much?
Don't use it then.
Its a win-win for the developer AND users. Until better way to reward devs is found
we have to cover electricity costs 5% is too much and he charges that much because he knows we don't have any other option, if i'm not going to profit (electricity is 80% of my mining revenue + 5% dev fee + 2% pool fee) after paying for electricity then what is the point .....
also 2 x faster 100 x faster difficulty will normalize that when everybody starts using that miner
devfee should never be over 1 ~ 2 % as a maximum because tons of users will be using that miner and hash for him at no electricity cost so why be greedy, i mean the dev will still end with a huge amount of electricity free hashes ...