There are important differences between Martin Allen and Ian Holloway. Allen's behaviour got him dismissed for "non-football reasons". He left his successors Megson and Holloway a huge squad with a large number of very poor players. Megson got out very quickly.Holloway tried hard to turn things around but failed. Being unsuccessful as a Leicester manager does not make Holloway an unpleasant character; that is an important difference between the two men.
What Allen and Holloway did have in common was that they were hyperactive. There are times when what is needed is a manager to "steady the ship". Following Martin Allen we needed a calming influence and that has been what we got eventually with Nigel Pearson.
The ultimate condemnation of Martin Allen is that he had a close season in which he brought in 14 players not one of which is in the present team. Compare that with Nigel who when Mattock is injured brings in Berner, when Tunchev is injured brings in Brown and then brings in Bunn for Martin. Now that is a sign of good management.