Stoke's transfer policy has been a masterclass in not what to do if you are a midtable club. Like West Brom, they had their big loan signing from PSG that they had no clue to integrate into the first-team set-up. Like Swansea, they let their best attacking options leave without much thought of how to replace them.
They seem to have a lot of turnover with players being signed from abroad, who end up on loan after a season or two (i.e. Bojan, Wollscheid, Imbula) only to be sold at a loss. The warning signs were there last year when they were still relying on the likes of Glenn Whelan. They've brought in plenty of players from bigger European clubs, who have either lacked the discipline, professionalism or fitness levels to remain at those clubs.
I think one thing that this season has shown is the dearth of attacking talent in the bottom half. It used to be that a few of these sides would have maybe one first-choice forward capable of scoring 10+ a season. That doesn't seem to be the case anymore. Given that Stoke signed nearly half a dozen defenders this season, their defensive record looks even worse. I'd love to know why £18m for Wimmer, who couldn't get a game at Spurs was seen as being good value.