It seems to me that you are looking for a solution and the only solutions that I know of is to buy Lindes or driverless forklift trucks. Everyone has an opinion about something, both positive and negative. I don't know who your local Linde or Cat dealer is but I can guaranty that the have customers that love them and they BOTH had customers that quit them because they thought they incompetent or a bunch of rip-offs. Every company does, including yours, I would guess.
In your industry high maintenance costs are a given but you can minimize them by having properly trained operators and properly designed forklift trucks that are made specifically for your application and those are called Linde's.
No I am not an apologist for your Local dealer but I do know, after 34 years in the industry, that you don't lower your maintenance costs by buying cheap forklift trucks and wonder why they break so often.