People are also trading
@xjp It's simple, when you're considering a trade just make sure you add in the interest rate to calculate the true ROI, factoring in how long you expect to hold the position and how far out the resolution will be (some previously negative ROI bets will now be positive). But don't do this for unranked markets. Or markets that may never resolve. Also if the market has a significant chance to N/A, you'll need to adjust for that.
I have taken some time to consider this but I'm probably going to just vote See Results:
Genuinely, it seems like you want BOTH systems.
The daily free loan is a genius proposition that increases user retention with low risk and makes people feel like there's something to come back for. It was probably a little too generous overall.
The margin loans with interest also seem like a nice feature for users who are interested in them, but with P2P loans available it's not clear how necessary this has ever been.
If I had to pick one I'd say the old system but probably with modifications.
I started typing things but it's going to be way too much for a single comment. I'm just going to pick a selection and keep it really short:
I should be able to see all of my outstanding loans in a single place (new column on user profile Trades tab would be a perfect match).
I should be able to pay back the loan on a market if I'm uncomfortable with its size.
I should be able to mark a market as "not taking loans" if I think it's volatile and I don't want to be in a hole.
The baseline system is already complicated enough that the median user only "roughly" understands it. Don't over-weight any argument against complexity -- it's going to be fairly complex no matter what. It's more important to have a complete and coherent plan than one that every user can fully understand with 3 sentences of explanation.
I still like the idea that 1/2 of your daily loan is computed in the current fashion and the other 1/2 is computed based on current value of the shares. (There is an entire book here about how to avoid 'gaming' this but it's certainly possible.)
If a loan is underwater you should claw it back at a rate similar to the rate it was doled out. Don't leave the user with a 1000 mana negative balance on the last day if they could have taken it back 25 at a time for a year.
Commission some users to come up with a justified plan for the loan rate/curve/risk metrics that will work within the system you want. You have some incredibly dedicated users who care about this stuff and can give you something tuned to the type of trading you want to see on the site. Way better than just guessing.
@Eliza Also, you absolutely need to avoid blowing up users who have established considered positions based on previous iterations of the rules. There are any number of ways to make this right, from "you're grandfathered in" to "here's some mana to fix your position".
It's a really good thing here to have a plan prepared/announced for a period of time before enacting it.

Thank you, market context AI generator. You have kept me abreast with only the most factual and up to date of details upon which to base my vote
@Simon74fe I've seen several people make this argument now, it sounds good.
I've also seen people say that all of this is too complicated and it's not worth it.