I won't be able to make the meeting, but can leave some thoughts in advance.
I think merging GUI development back into the main repo would quite be a regression. As far as I'm aware, for non-GUI contributors, it's been a great filter for keeping all the not-related-to-bitcoin GUI stuff out of their inboxes (probably similar for the thousands of bitcoin/bitcoin subscribers).
In general, I don't think we should be returning to a state where we're having conversations like this, bitcoin-core/gui#674 (make the desktop icon more round on macOS to better fit macOS rules) in the same repository that we're trying to fix actual bugs and do things like this: bitcoin/bitcoin#25717.
In regards to review/contributing being more difficult. I think that's just a reflection of the reality that most devs don't want to work on/review the GUI, and I think it'd be suboptimal if we pulled the GUI back in, and that started taking away (in any amount) from the already severely limited review capacity we currently have in bitcoin/bitcoin.
At a higher level, it'd be great if someone working on the GUI could explain what the longer term plan for it is. My understanding was that the current GUI was almost in somewhat of a maintenance mode (no real new features / development etc), because there's more effort being spent on https://github.com/bitcoin-core/gui-qml.
However progress on the QML GUI seems slow, and afaik the first iteration won't even have support for wallets. Which means it won't be able to replace the current GUI for some time? So what are the timelines for that, or any sort of switchover, and how is it all going to work etc.