I'm really surprised by the number of people who are saying get rid of the Smiler. I thought I was literally the only person in the world who didn't like it, clearly not.
In terms of improving the park, when installing new rides, areas, projects and attractions, Smiler (and to an extent Rita) can be used as examples of how NOT to go. Smiler was rushed and although the theme is good and the ride is popular it certainly doesn't feel at all world class if you ask me.
To make a world class new ride, they should go back to John Wardley's old philosophy of wanting the actual ride itself to be simply the mode of transport for guests to be transported into immersive themes. This way you don't get some bodge job rides added and it feels more like a long term, carefully thought out project rather than just a ride which was shoved in and a theme quickly cobbled together.
I would like to see the cross valley woodie plans resurrected and less emphasis put on gimmicks and unique sellign points.
I would also like to see queue time information displayed more around the park. On my last visit, I noticed the LED board at the end of Towers Street has been removed and the one at the entrance to the Towers was switched off. I would like queue time info at the entrance to every ride. i know PortAventura isn't particularly popular on this forum but they have LED boards (previously chalk boards) with queue time information of ALL rides at the entrances to every major ride. That way if you get to a ride and the queue is too long you can look to see which rides have shorter wait times and go there.
The entrance and Towers Street needs a complete overhaul and I also feel that new rides and buildings should be more sensitive to their surroundings. Thirteen is a perfect example of how it should be done. Spinball is a perfect example of how not to do it. It sticks out like a soar thumb. The same can be said for the overly bright Skyride cars.
There's more I can think of but it can't all be done overnight. The overall feeling I have is that Alton Towers should take more pride in what they do and run their theme park for the love of running a theme park and look at everything from the guests' point of view. I know they're a business and that this can't always be the way, but they can surely get closer to it than how they are now.