It's been a while since I last played RCT2, so I'm not quite updated on Colossus' layout, but could a dual station loading work, given sufficient refurbishing? Or even a double-length station?
I see the problems associated with Möbius operation. Notably, the extreme duration of the ride (absolutely killing the throughput unless many trains are operating) as well as the need to maintain twice as much track (and subsequently, two sets of brakes and lift hills) for the same amount of riders.
Another option: Would it be (economically, space-wise, or legally) feasible to just tear the ride down and replace it by a single-track, "standard" big woodie? I mean, at the moment it sits there without many days of dual-train operation. It has been in the park for many years, and will eventually require a significant hardware upgrade to stay reliable. I'd even guess many of its current parts would need to be outright renewed anyway, seeing as spare parts are harder to come by as industry standards change. If they want to keep the ride running, they have to spend a lot of money on it. If they want to refurbish the ride up to what parkgoers expect from modern coasters (giving it relevance once again in the same way as Texas Giant), they would have to shell out even more, effectively building a new ride entirely. But that "new" ride would still be based on a concept from 1978. It wouldn't be sellable as an entirely new ride unless they made some really big changes.
Then, what can be changed about Colossus while still keeping it Colossus? The twin tracks theme is too big to simply scrap. If they did that, they might as well build a new coaster. On the other hand, if twin track operation is rarely used (or demand rarely calls for it), is there still a point in keeping it? Again, you're effectively building and maintaining two coasters for the draw of one. No matter what you do, the guests will see it as one single attraction, even though the two tracks technically are independent of each other. If dual operation on a refurbished Colossus won't be more prominent than it is today, it would be a waste of money to "remake" it into another twin racing coaster. In other words, for a refurbishment to make sense, SFMM would have to commit themselves to continued dual operation. And if today's standard is anything to go by, dual operation doesn't look like it's very much needed.