I is historically the smallest and simplest, and therefore also one of the most easily confused letters of the alphabet. Lowercase L is simple too. In a sans face like Gill Sans, one is hard-pressed to find an iota of difference between the two. The dot atop i and j can also correctly be termed a tittle, though dot’s generally clear enough.
Pieter van Rosmalen’s Nitti uses broad slab serifs on i to inhabit a body that’s otherwise an impossible fit.
