Splitter was essentially replaced by Aldridge, tbh. Or if you're talking about the starting center position, Splitter was replaced by Duncan. Add in Old Gasol and Dedmon in the meantime and I don't think Splitter was missed too much, if at all.
But, yeah, Splitter is a pretty good comparison for Poeltl. Peak Splitter was better than current Poeltl ... but even he wouldn't be worth a ton in today's game. He was one of the best pick-and-roll bigs on the planet but he couldn't do much once removed from Ginobili and Parker.