I don't like the idea of the entrance relocating as the views from towers street are great, however logistically and in the interests of the park being able to handle higher customer throughput in the future, it makes sense and I'm sure will happen, soon.
Getting back on the original topic however, I still think that the monorail plays an important role within the park. Before the entrance moves (or if it never does) it is the best way or moving people from the car parks to the entrance on mass relatively quickly. I agree that it does need an upgrade, mainly just to ensure the queues are kept to a minimum. More trains should be running most of the time and the ability to add more trains to the rail should be improved to allow them to quickly be added.
The suggestion of replacing the monorail with a different system would simply be impractical and too expensive in most situations. The only alternative I could see which could be cheap and simple, is to use tractor driven road trains. Vehicles travelling along a traditional tarmac roadway, which can add longer trains easily, or can have more trains bought into operation immediately would be cheaper and easier to run, replace and repair. I also don't like this idea too much because you lose the over park sections, however if cost of repair and maintenance are the main issues threatening the monorail then this solves this problem fairly easily.
For the future, if the monorail was refurbished and the entrance did move, it could still serve a purpose as an in-park transport system, spreading out the crowds from the entrance to two separate areas of the park quickly and efficiently.
Alternately if the system of tractor driven trains was used, and the entrance still moved, they could be used as a general car park transport system to cope with ever expanding car parks (Disney style), or even an in park transport system however this doesn't seem too practical.