So, end of May I went trough T3 for the first time after years at T2. Upper floor check in level at noon on a sunny day was a sauna, especially at far end of terminal where immigration is located my guess there were 27-28 C at least. Even considering the crowd due to holiday season in Indonesia both security checks and immigration were quite quick, for security checks priority lines are only available for Garuda and Skyteam premium passengers, thus all other airlines go trough normal lines.
About immigration was a kind of a mess, not due to the crowd at the end was not that big, but there were nobody to supervise the lines, thus either local and foreigners where heading to any counter without control even filling diplomat/crew and foreign permanent residents lines that are normally empty. while in line I then noticed then that at far left there were two empty lines for "Priority" and headed there, it seems all biz class passengers can use these counters either Indonesian or foreigners.
Flying WY I got the access to Saphire lounge near gate 7, not the Saphire Premium Plaza at gate 5, I guess is the sub par downgrade of this last and to be honest one of the worst settled lounge I can remember in Asia, TK, CI and other Chinese airlines plus credit card customers are placed in this lounge as well, let's say it reminds the "quality" of Pura Indah Lounge at T2 but you even have to go outside to use the toilets and to check the flight monitors as there aren't any inside.
At the end I also found that T3 is not bad but heat issue and lounges offering need a steep improvement.