Since PE is take some inspiration from Planescape Torment, I would hope Obsidian really tunes its' conversation/description and lore system UI well. One of the things that I really got upset with PST was the text was a bit unreadable at times because the fonts were to small.
So, my simple suggestion is:
1. Make sure that there is an option to adjust the font size of the conversation system, inventory description, lore books etc. (anything with a some amount of written text). Some of us are no longer young-un's anymore and having to squint and read on a large monitor is not very pleasing, to say the least.
2. Color coding when different characters are talking. I AM NOT TALKING about Mass Effect Paragon BLUE and Renegade RED here. What I am saying is when there's a multi-threaded conversation between the PC and his companions, things can get a bit confusing. Color coding between different characters conversations could make things a bit less confusing. For instance:
PC: I don't think it's right to just leave him there.
Companion 1: Come on. Let's just leave him. He's not going to make it, we have to hurry.
Companion 2: We can't just let a person die without even trying.
PC: Let's see what we can do for him first.
3. If there's any codex or in-game books, could we have some form of control over the font size. The Dragon Age: Origins codex is a typical example of this annoyance. It's great to read but the font size is so darn small, I have to squint to actually read it.
4. Font used and Background Color
Some fonts are hard to read. Please don't use stylish fonts to evoke a fantasy feel if it's at the expense of readability. Or allow us the option to change to a few different fonts. And please don't use a grey colored font against a chocolate background ... The Dragon Age Origins codex had something like this and it made reading near darn impossible.