Speaking at Hampden Park where he was helping to publicise Ladbrokes Live Football show, McCoist admitted knowing little about Caixinha, currently in charge of Qatar Stars League side Al Gharafa.
However, he revealed that, were it down to him, he would look to persuade two former Rangers managers, Smith and Souness, to return.
He said: “I don’t know the gentleman (Caixinha), the same as 98 per cent of Rangers supporters.
“I would clearly wish him all the very best, but I would be very surprised if he turns up with a magic wand.
“He is going to need help, investment.
“We have maybe slightly improved, but we needed investment two or three years ago and we need investment now.
“In my last year we were miles away from challenging Celtic and that’s where we are at the moment.
“What I would have done is get Graeme Souness and Walter Smith in a room and locked them in and not let them out until they agreed to come back to help us.
“I don’t think they would have done it unless they were promised investment, but Rangers need leadership.
“They need direction and those two men I have mentioned would have given them that, but I don’t think it is going to happen.”