If I was SkyTeam I would not Let Garuda Indonesia join, & probably let MH or even PR ahead of them! I wouldn't risk my life flying with them, even though they are allowed back in the EU. I think CI also wants entry next year, I really want them to join!
Vietnam Airlines, yes is quite small but it is trying to expand and is considering flying to destinations such as LHR, PRG, BNE, PER, LAX, SFO & AMS. It will help SkyTeam's coverage in SE Asia, (even though it doesn't even fly to Indonesia). It would align SGN & HAN as SkyTeam HUBs, as SGN is in the middle of SEA which can be used as an advantage. This would actually take some flights off current BKK flights and be transferred to SGN which would build a new bigger airport the size of BKK called Long Thanh International, A new playground in Asia for SkyTeam.