wow... these backroutes are tough to get rid of. And I'm not entirely sure I want to either. You said you liked the level and you don't think it's too easy as is? The thing is, the required saved # is a factor here... If your interested, I attached my solution for feedback.
Very nice. Well, if you do decide to eliminate my solutions, since you use the miner merely as a turn-round, while both my solutions need it for digging, you could kill both at once by replacing the miner with a second walker or jumper. Unfortunately, that would make the use of the cuber much more obvious, and eliminate some red-herrings that I spent a while on before finding the solution(s).
Conversely, this may not be the direction you want to go in, but I just noticed that the level could be tightened while still allowing both my solutions by requiring 59/60 saved. My second replay already saves 59, and in my first solution, using your idea of jumping from the very edge of the wall gets rid of the need for the cuber.
EDIT: Another possibility is to make it a true one-of-each: remove one climber and floater. That kills my first solution but allows my second (I used a second floater to save an extra lix, but without it, I still save 58.) Your solution can quite easily still be done.
EDIT: In fact... well, just look at the filename