Honestly, I can't believe we have to keep saying this. The message center should show the full complete text of each item's subject line without me having to click into it. Even if that means that two or three lines per item are needed.
The new Admin Center does show more of each subject line than the previous one, so that's a plus. Now go all the way and show the entire line.
Recent example of a long one: Change in enrollment workflow with Intune Company Portal on corporate iOS devices authenticating with Setup Assistant