The Mine Train was actually apparently part of the original expansion before the Tremaine Chateau and Pixie Hollow version came about. You can ask Lee for more details but I recall him and other insiders here stating this, the chateau version was likely an attempt to cut costs until they finally decided to include the coaster in the final version. Not a bus driver rumor. It's quite bloody obvious from just plain common sense (based on what both Universal is able to accomplish now as well as what Disney USED to be able to pull off) that the Mine Train is taking too long. Disney themselves have accomplished infinitely greater things while working around obstacles inside parks in far less time and with immensely less money (even adjusted for inflation). If you're going to diss insiders here who have proven themselves too many times to list, then go ahead and call it bus driver info and continue living in that Fantasy Land (just realize that the Fantasy Land you're living in was value engineered and STILL not complete after well over 3 years of construction time).
Meanwhile up at Universal, Diagon Alley is just about complete and effectively "began" when Jaws closed in early 2012 (they had a lot more work in order to clear a place than New Fantasyland, which had very little left to clean up from 20k Leagues). They also built Transformers in no time flat despite also being in the middle of a functioning park. At this rate the upcoming King Kong ride will be finished well before Avatar too (which I gather hasn't begun any substantial construction progress yet), and that also has a park to work around as well. There's something very obviously wrong with the way Disney is handling construction time and budgets, especially given the quality of the final products.
As for your claims about waning popularity for EPCOT rides, Imagination 1.0 was manipulated by park ops to make it seem to have waning popularity. It was quite common during the mid 90's to see cast members leading people away from the ride and shuffling guests over to the 3D movie instead. You can again ask people like Lee or Martin about these actions, but it was done due to the operating costs the ride commanded, and the waning attendance levels caused by intentional manipulation were used in the corporate ranks as an excuse to gut it and replace it with a ride that cost far less to run. When left to its own devices, Imagination was quite a popular ride. And even with that manipulation it still commanded infinitely more people than the absolute abysmal failure of the current version which most people know to avoid like the plague. Horizons and World of Motion also likely suffered from similar fates to some extent. I am aware that GM wanted a new ride in place of World of Motion, but it was Disney's fault the new ride wasn't as good from a show perspective (early concept art for WoM also actually depicted a Test Track like thrill ride accompanying the main attraction). Horizons was apparently going to get a makeover like SSE's 94 refurb until they decided to reformat it into a glorified space spinner. And i'm not even sure why they shut down Wonders of Life.
There's an unfortunate and completely BS argument going around that EPCOT was in some sort of dire trouble due to guests not liking it. Some even have said it was a failure even when it originally opened and no one ever liked it in the first place (claims it was a financial disaster). Couldn't be more wrong. Even in the 90's (until they began manipulating traffic for rides shortly prior to the park's Gemini devastation), crowds close in size to THIS during some of the busier seasons were quite common-
http://forums.wdwmagic.com/threads/look-how-crowded-future-world-used-to-be.875245/
That video was taken in 1989 (when the park and its classics were already established and older), but there were plenty of times when those rides continued to command similar crowds throughout the early-mid 90's, before park ops began manipulating the crowds away from them. That video is also quite a testament to just how loved these rides were despite the false claims people have levied towards the park. All of Future World's classic rides were massively efficient on crowds, very long continuously moving omnimovers that ate through masses of people like they were nothing and kept lines moving incredibly quickly. The fact that these rides still got those huge crowds despite the incredible capacity and efficiency of all those rides is truly impressive and says a lot. This was also well before Fastpass was created (which artificially inflates lines to several times what they should be), and when Future World had multiple great rides to absorb and spread out crowds well.
The reality for park guests is quite different than what the manipulated data seemed to indicate to the non park-going corporate leaders. There are a few simple facts that reasons their replacements get the lines they have now is due to, 1- the advent of Fastpass which has been shown to manipulate ride lengths to several times what they normally would be (the wait time for Mermaid with and without Fastpass has been mentioned here on multiple occasions), 2- the rides in general are nowhere close to being as efficient or high capacity as any of the classic Future World rides, and 3- the options for quality rides at Future World has become incredibly limited with the 90's purge (there aren't enough popular and quality rides to help even distribute crowds). If Soarin were capable of the same capacity and efficiency as the likes of the classic Future World rides (as well as a lack of fastpass along with a buffer of alternative quality ride choices in the park), you'd not be nearly as impressed with the sort of lines it commands.
