New room list has font-weight: 600 (CSS class .mx_RoomTile2_nameHasUnreadEvents) for rooms with unread messages, the default weight being 400, I believe. Normal bolding is weight 700. I'm a person with normal eyesight and pretty good monitor (admittedly not calibrated), and I'm unable to reliably discern between unread and read rooms. This must be way worse for vision impaired users.
Observed with the newly styled Element (https://app.element.io/) since today (2020-07-15).
I'm unable to reliably discern between unread and read rooms.
There is also a grey dot to help with this;

They grey dot is there indeed, but as it's separated from the room name by some space, at least for myself it's harder than before to discern which rooms have unread items.
Yeah, this is pretty bad now. I feel like using font-weight in general for this isn't the greatest. For example here is the distinction between unread and read in Discord's dark mode:

There is a very clear visual difference between grey and white text for the whole channel name.
I've always struggled with it in Riot, but was generally able to at least tell the difference. I honestly can't anymore. I didn't even notice the grey dot, but it gets lost among all the other things that can be in that right hand column. Can we at least get a setting somewhere for making the contrast muuuuch easier. It'd also be nice if the room list order didn't jump around constantly (this isn't the "always show new activity first" thing - sometimes just clicking around on already-read rooms causes the order to jump around).

Here's sample of what it looks like, I tried font-weight: 900 and it's better.
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Yeah, this is pretty bad now. I feel like using font-weight in general for this isn't the greatest. For example here is the distinction between unread and read in Discord's dark mode:
There is a very clear visual difference between grey and white text for the whole channel name.