Please take it on
I know myself and a number of my guildies would be very appreciative if someone took on the job of updating CoreUI.
I have muddled through since Techy stopped playing (last April), managing to change Core so that I can display buff names alongside icons in a scrollable buff bar, adding in the code for the charge bar, the increased inventory etc. I'm not an expert with coding though and don't even know how to pack up my UI changes so that others can use them.
I still find CoreUI to be the best custom UI for Vanguard and would really enjoy seeing it picked it up and updated.