First of all scoring in the regular season is less valuable than in the playoffs. His points per game isn't particularly impressive when we talk regular season, though he did have 18 points in 10 games to end the regular season, and had a few stretches where he had a few games where he was 2 PPG. But looking at 16 game stretches isn't really a thing in the regular season. Looking at a 16 game stretch in the playoffs is much more impressive because you have to actually get there, play that many games, and also play at a high level still.
Sennecke is 286th in points/season and 300th in ppg for a draft eligible. He also happens to be 78th for a 16yo in points/season and 74th in PPG.
Those aren't particularly bad numbers, but looking only at the numbers for Sennecke is somewhat disingenuous in the first place he isn't a pure skill top 6 forward or bust guy. He's 6'3, plays defense, and is physical. Can't really say the same about a lot of guys ahead of him.
Similarily Kasper Haltunnen just set records for most goals and points by an import player in the playoffs and tied Boqvist for 2nd overall and most by an import in power play goals. But he had a PPG similar to Sennecke's in the regular season, and still had close to that PPG in the playoffs.
Personally he's not on my radar in the top 5 or probably top 10, but only looking at stats doesn't really give you the full view either. If that was the case a lot more people should have had Cristall and Noah Dower-Nilsson a lot higher than they did!