There is one parallel to draw some comfort from and that is Newcastle United.
They sacked Hughton who was doing reasonably well and replaced him with Alan Pardew. He had been very successful with Reading which led to him getting the West Ham job.
He took West Ham up, got to a cup final and finished 9th. He then precided over their worst run of form for decades and was sacked. He then took over at Charlton mid way through the season, ultimately seeing them relegated from the Premier League (possibly harsh to blame him). Subsequently after failing to get them promoted straight back up (for which he is fully responsible), he led Charlton to bottom of the Championship and was sacked. Following this, Charlton went down again.
He then went on to deliver some modest success at League 1 Southampton but he was sacked due to dressing room unrest and clashes with the owners.
There are real similarities between McLeish and Pardew - both experiencing a real mix of success and failure. This can be extended to many managers such as Sam Allardyce, Paul Jewell, Avram Grant, Lawrie Sanchez - managers who can clearly point to certain successes as well as failures - the list goes on.
The problem - such managers, including McLeish, have obvious limitations in style and ethos - their variable form also makes them a clear risk meaning that they do not demonstrate the assurances over success that a club who claim to have the ambitions we do should aspire to.
This is a backwards step most certainly and whilst I accept there are some limited benefits i.e. our defence last season was atrocious and that will definitely improve meaning it could work out but in the event that it does, I would struggle to credit it to good judgement. The past proves this. Most certainly if McLeish is successful, we will all be delighted, but it will be the luckiest decision Lerner has made and even if it pays off, the risks he is willing to take over this football imply his inability to make rational footballing decisions.
I don't want him to sell up but I would urge him to appoint a CEO with proper footballing credentials to avoid future embarassments.
There are many managers out there who we could almost certainly employ that come with better reputations and credentials. Some are in work, some are not