I cannot make my mind up on this.
He reveals himself to Anakin, and allows Anakin to leave. As a result, the greatest swordsman in the order and some (apparently) gifted others rush to face him.
Fortunately for him, he is able to kill three with ease. Then he is part of an epic duel that people debate he may or may not have 'thrown' - but did he design that situation, killing Windu personally and putting Anakin in an impossible situation that finally turned him, or was this out of his control? Did he really want to face Windu and have a battle that most feel was a defeat and the reason for his disfigurement?
(Related prompts, but all part of this question: Did he feel only he could kill Windu? Did he want to kill him personally? Did he feel Order 66 wouldn’t work if Windu was out there? Was this very precise situation the only way Anakin would fully turn?)
To summarise: Did Palpatine want or need to face Windu, or was it a dangerous risk?