I have doubts that exchanges are going to pay you to have their exchange added to the bot. Most expect it the other way around. I think if this doesn't work out, a better method would be to implement a separate auto trade fee so that any successful trade that happens (buy or sell) would include a small 0.1%-0.5% fee added to whatever the exchanges fee is. So in other words when the trade successfully goes through (the open order is closed), the exchange gets it's fee as usual and the bot also sends a separate 0.1%-0.5% to your btc address. I think this would please everyone and here's why:
1) The bot would remain free.
2) All exchanges could be included (eventually)
3) The more people using and making trades with the bot the more money you and your company would make.
4) The users don't have to deal with switching between "supported exchanges" and "unsupported exchanges".
5) It all happens in the backend and would be auto calculated within the rule set so the user still makes a profit.
just my 2 cents. I know I'd personally stop using the bot if BTCe was no longer supported mainly because I don't want to move my btc around again.
I have to disagree to your proposed fee %. I've been trading on 1 minute algorithm since December (mainly Cryptotrader.org) and that I support with Qt Bitcoin Trader (e.g. stop loss). This means tens, even a hundred trades per day. BTC price volatility in this time frame is usually 0.5%, on good days 1% and on extreme days it can be more than 10%. Exchanges take 0.4% or 0.2% of each trade already, so from usual 0.5% this leaves maximum of 0.3% for relative profit (and here I say relative, because you sometimes can't get profit for days or get negative price development for longer times). 0.1% would therefore mean 1/3 of my best profits. This would automatically mean that I would reject this service.
Cryptotrader has been for long time now using a user license policy where different features are available at different monthly fees. I have some difficulties that sometimes this is for me 100% of my monthly profits, sometimes even 200%. However, there seems to be several other customers on the service so the license policy works. As the trading bot doesn't have very high intelligence inside (e.g. logic patterns, algorithms for trend analysis, auto-tuning trade patterns) I would recommend a Basic fee of e.g. $5 / month / exchange (substantially lower fee than CryptoTrader). Unlimited exchanges would be inside Pro feature and that would cost e.g. 5x Basic. As the next versions are coming with new features (like 3EMA trend tracking and Decision models that support parallel rules) these would be included to Medium and Pro accounts that have much higher fee.