As described in this forum post
https://answers.microsoft.com/en-us/msteams/forum/all/teams-planner-links-showing-as-large-icons/4e757700-5fa9-4f0a-b400-b476f0c4ca1a
the layout of Planner task cards with an attachment of type "link" for which "Show on card" is ticked has changed for the worse recently.
The feature adds a clickable link with a small icon before it to the card. A few days ago, this was all it did, and we liked it.
Now, the icon is also used as the preview image, larger than the card itself (see screenshot), wasting precious screen space. There seems to be no way to disable the preview image (other than not showing the link on the card at all). This makes the feature unusable for us. We want to have the link right on the card, but not the huge preview image.
Please revert to the old behavior OR add an option to attachments to "Show as (large) preview image", which one can disable if desired.

Start a conversation about a Planner Task

When you have a Planner Board setup within your team you can have a conversation about the whole board. But since this board is likely to contain dozens, if not hundreds, of Planner Tasks having a generic conversation on all of them is quite cumbersome. Within a Planner Task you can comment, but these are sent as emails to the group and are not showing up in he Channel Chat.

What would make Planner really work for us is when you can start a conversation in Teams about a Planner Task. just as you can start a conversation about a specific document in the Files Tab and not 1 conversation about the whole Files bucket. And the icing on the cake would be to replace the comment section in Planner with the Teams chat that was started.

This allows our development Teams to truly utilize the power of Teams and Planner, because it allows them to have a conversation thread per Planner Task (card) which matches perfectly the conversations we are having day in and day out. We are talking about specifics tasks and not about the whole project, so would be great if the tooling would allow us to do the same.

It would be great to be able to create "milestones" in Planner, where we can assign tasks as being part of certain milestones. We can sort of do this with the Checklist, but sometimes each checklist item deserves it's own discussion. We also have the tags, but I'm picturing something a bit more explicit, similar to Github issues/milestones (see image). By assigning tasks to milestones, you can see clearly that the milestone is "met" only when the tasks are done. Currently, we've been setting milestones by creating separate Plans. This might belong in the Planner forum, but my only exposure to it has been through Teams.

Had an interesting use case pop up today -- one of my team members sent a review request as an email to the team with a link to a Teams-based document. When I asked why she sent an email, she said she considers email to be more "visible" than things in Teams, and that sometimes things are lost in Teams.

Further investigation concluded that if we had the ability to convert conversations or bits of conversations into actionable items and add reminders/notifications to those somehow, the tool would be infinitely easier to use.

I think it is critical to have the ability to make a post or comment "actionable". Actionable means turn it into something with both state and timing. For example, today in Outlook I can create an Outlook Task from something and assign it a state ("in progress") and a timing ("notify me in 1 day" or "due on X/Y/Z at HH:mm").

We currently have the ability to bookmark/save posts or comments, but this does not provide me with "actionable" results. To accomplish this, I have to copy and paste into a different application and maintain synchronization between them.

A cheap solution would be, as suggested elsewhere, categorized bookmarks -- so I could create a category called "TODO" and another called "In progress". When I want to remember to do something, I'd bookmark it into the TODO category; when I start working on it, I re-categorize it to "In progress". However, this provides no timing and no notifications for me and is essentially a very dumbed-down solution.

Ideally, I'd be able to create a Planner task from a post or comment and then I would have a visual on what I need to do, along with moveable state AND notifications.