Deane, 45, currently manager of Norwegian side Sarpsborg, spent two separate spells as a player with hometown club Leeds and three different stints with the Blades during a 21-year playing career.
"When I think of Leeds, I think it once as a mighty club, I hope it returns to where it should be, but it's going to take time," he told Press Association Sport.
"There are clubs which have caught up, there have been a lot of changes and it's been hard, in terms of a model, turning it into something which is free of its debt. I think the fans have to be patient.
"I wish both clubs well. To me, both should be in the Premier League.
"Perhaps there has been mismanagement over the years and I think, in life, you can have too many hangers on and both clubs have perhaps had too many hangers on.
"You need to get a balance between a business plan and also more brains and it's not always worked that way with clubs.
"You have to have a long-term plan and I think sometimes fans have to be more patient with ambitions, otherwise you get what happened to Leeds, where they had a situation with more players than they needed, on big wages.
"Sheffield United, I will always have a soft spot for them and will always look out for them.
"I was home the other day for a couple of days and watched the game against Coventry on TV and it was quite sad really, because I don't think the club has been as low as that in 20-odd years.
"I joined them in 1989 when they were in that division, but we were doing well.
"It's sad to see such a massive club with so much potential going through the problems that it is.
"I'm sure there's a plan in place - I hope there is - to turn things around, but it's going to take time, good coaches and good managers coming in and investment as well."
- Sports & Recreation