Essentially, there are a few different things people get confused about.
1) Why profitability seems to drop (the last question here). This could be solved in the manner that Clevermining has done, by tying it to a % profitability of LTC. So that when the market as a whole changes, we're still X% of LTC. It could also be pegged to USD, which takes out the factor of BTC market fluctuations.
I am for displaying all the stats: BTC / 1MH, LTC / 1MH, %LTC, and USD / 1MH
Where LTC/1MH is at the current exchange rate of ... BTC/LTC
Where %LTC is LTC/1MH compared to what we could have expected if mining only LTC
Where USD/1MH is at the current exchange rate of USD/BTC
2) Why the amount earned changes, which is completely dependent on maturation time of blocks, and price fluctuations within that time (auroracoin's 16hr maturation time is a great example). Any price changes during that 16hrs make us look like we earned more or less during that time period, and as a secondary step of confusion, the amount we "earned" is not the amount we paid for that day (confusing). One option here is to avoid coins with long maturation periods, and I think this needs to be done a bit (having 90btc earned in auroracoin was probably too much), but when they're more profitable (and the market looks good), I'll have people yelling if we're not mining them.
The other option is to rework our accounting to list approx prices based on when they were mined, rather than prices at the current time. So if we earned 10 aurora coin when they were worth 1btc each, and the price went up or down, we would continue to show those as worth 1btc each. This is closer to what people like hashcows do, as they provide stats at the time it was mined, rather than at the time you exchange them for btc. But it brings up a major problem that during drops in prices, our stats may show that we earned a lot, and paid significantly less, and yet again, more people yelling.
If you are going to rework the accounting system, then I suggest adding a column "BTC gain/(loss) on exchange". So, people can see the gross earnings, and adjustments due to altcoin conversion.
Which brings up a question: Is the gain/loss (including the coinmarket.io problem) charged back to the original accounts, or spread over the current day's account? Since the coins show up as "unexchanged", it can be charged back. Do you distribute BTC on exchanged coins prior to receipt from the exchange? I think coins held at an exchange should show up as "unexchanged BTC_coinmarket", and be distributed when you receive them. Hold them in each person's account as unexchanged. Maybe flag the name of those coins, so we can see our individual exposure.
I think you should only mine coins that are on an established exchange. At a minimum, it shows a certain depth to the market for exchanging the coins.
