I’m not sure that Wicker Man being built was necessarily the sole factor in The Flume’s demise, or even much of a factor at all.
If the April 2015 screening opinion is anything to go by, it sounds like they very nearly did build a woodie somewhere else (it described a “timber truss structure” in Forbidden Valley), and Wicker Man in its final form was only conceived after the Smiler incident.
The fact that Logger’s Leap closed in the same year as The Flume, and that they both closed in the aftermath of a catastrophic accident when Merlin became hyper focused on group wide H&S, would suggest that there may have been unavoidable circumstances resulting in the ride’s closure whether Wicker Man had been built or not. In that case, I’m extremely glad we got a great woodie to replace it instead of just having it SBNO for years on end.
I remember hearing a rumour that part of the H&S response to the Smiler incident entailed fitting some sort of additional H&S measures onto Merlin’s log flumes (something about some sort of system to be able to hold boats at the top of drops to prevent them from sliding down if there was a blockage at the bottom) that costed a fairly large amount of money. The story I heard was that Dragon Falls justified having this work done as part of (or possibly preceding) the Tiger Rock refurbishment in 2018, Logger’s Leap was originally supposed to have this work done, but the money went towards DBGT’s rework at the last minute and Thorpe’s efforts to revive it were a bit doomed after that (hence why the ride stayed in limbo for about 3 years before Thorpe finally announced its removal), and The Flume was not considered worthy of this work, therefore it was removed with Wicker Man concocted as its replacement.