Keep that nice original A1200 going - as-is. Put some extra memory in it and enjoy that work of art.
Why break something that works beautifully to make a new basically same thing from it?
Alicia 1200 is very cool, with a few nice tweaks, but the expense to end up with basically same thing is significant. For me the drawback of these lovely boards is always that an original Commodore board must die. Now there are non-working boards, so that is a noble application of Alicia 1200 or ReAmiga 1200, but often those boards could be fixed or working boards are used to build these new formats. Cost is always significantly higher than original Amiga motherboards and in the end you'll need a keyboard anyway, so why not have it in the original beautiful wedge case.
Retro A1200 is a software emulation and in my view, not Amiga in any way.
If you're itching to build something different, consider a MISTress1200 running a MISTer DE10 Nano in a new Amiga 1200 case. Gives you killer capability, and most importantly, no Amiga motherboards need to be harmed. Overall, much cheaper than ReAmiga1200 or Alicia 1200 and also way way less trouble.