Comment 4 for bug 692778

> Perhaps an treatment solution to try would be some combination of the
> following:
>
> * the Ubuntu Mono (curved) lower case glpyh 'i', minus the top serif.
> * and/or a slightly large bowl/uptick to the tail perhaps in combination
>(if still needed to fill out the width),
> * possibly a touch of curved oblique on the stem echoing the recent
>design solution for 'ν' (lowercase nu) vs. 'v' (lowercase vee); (see also
>'τ' (lowercase tau))

The main feature of the Latin iota is it’s hooked bottom.
As long as the i has a hook, it will be confusable.
Serif or no serif, a more salient hook t, a curved oblique stem don’t make it clear which is which if both have a hooked bottom.

If you need a relatable comparison:
Imagine somehow an i with a left hook below the baseline (as was sometimes done historically in some contexts, for the sake of the comparison assume this is an acceptable style nowadays). This would be totally fine if there is no need to distinguish it from j.
Now design a j that is distinguishable from that i using serif or no serif, a more salient hook or an oblique stem. These are all inappropriate solutions, it’s not clear which is which (at least not without a clear context) and the j will just seem odd (compared with the user’s expectation).
The solution is to change the i to the more common form that doesn’t overlap with the j.