I like this move for both teams, actually.
With Henrique signed, Oilers don't need McLeod as a #3C. Simultaneously, healthy Arvidsson, Skinner and Kane make him obsolete in the top 6. If one gets injured, you can move up Brown or/and Holloway.
Buffalo has a large variety of players who are similar to Savoie, he is of course a little undersized.
McLeod is a solid #3C who still has a lot of potential. He is tall and a very good two-way player.
He was sheltered behind McDrai offensively when not playing with Draisaitl, which won't happen in Buffalo (so there might be something coming here). He is very good on the PK and has the speed to potentially keep up with anyone in the Buffalo top 6 when needed.
Does this move seem like an overpay? Yes, but only in a vacuum, and these don't exist in the NHL. It's pretty obvious that young everyday-NHL-centers with speed and size are valued highly. Savoie on the other hand is a little undersized and has yet to play a larger amount of NHL-games, let alone playoffs. You could also argue that Edmonton is taking a risk here as well.