I remember when it was Irvine's fault when Varela didn't work out and Clarke's fault when El Ghannasey didn't work out. I'd suggest it's more to do with Gnabry not applying himself correctly than Pulis not liking flair players which has been proven a myth with the inclusion of Sessegnon.
Pulis has only played Sessegnon since he has been doing more work on his defensive positioning - if he hadn't, he still wouldn't be anywhere near the team now.
El Ghannasey wasn't good enough, anybody who watched him could tell you that, while Gnabry is a German under-21 international who simply isn't the finished article yet.
Varela was a different kettle of fish. A Portuguese international, capped before and since, and he was a class above most. When he played, he actually made a difference, as we saw with a great assist for Saido (I forget who we were playing at the time). He was unlucky with injury, but when he was fit Irvine should have used him more.